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Carboidrati alla sera? Sì  

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Tropico
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Post: 9776
25/11/2012 9:14 pm  

E' un po' un luogo comune che i carboidrati alla sera facciano ingrassare.

Perdita di peso maggiore e cambiamenti ormonali dopo 6 mesi di dieta con carboidrati Mangiati Prevalentemente a cena
http://www.nature.com/oby/journal/v19/n10/full/oby201148a.html 2011
Questo studio è stato disegnato per investigare l'effetto di una dieta ipocalorica con carboidrati consumati per lo più a cena antropometrici, fame / sazietà, biochimici, e infiammatorie parametri. Secrezioni ormonali sono stati valutati. Settantotto agenti di polizia (BMI> 30) sono stati randomizzati a diete peso sperimentali (carboidrati consumati per lo più a cena) o di perdita di controllo per 6 mesi. Al giorno 0, 7, 90, e 180 campioni di sangue e spartiti della fame sono stati raccolti ogni 4 ore 0.800-2.000 ore. Misure antropometriche sono state raccolte durante lo studio. Maggiore perdita di peso, circonferenza addominale, e il corpo riduzioni massa di grasso sono stati osservati nella dieta sperimentale in confronto ai controlli. Hunger punteggi più bassi sono stati miglioramenti e maggiore nei livelli di glicemia a digiuno, le concentrazioni medie giornaliere di insulina e HOMA per l'insulino-resistenza (HOMA IR), T-colesterolo, lipoproteine ​​a bassa densità (LDL), lipoproteine ​​ad alta densità (HDL), proteina C-reattiva (CRP), fattore di necrosi tumorale-α (TNF-α) e interleuchina-6 (IL-6) sono stati osservati livelli in confronto ai controlli. La dieta sperimentale modificato le concentrazioni di leptina e adiponectina giorno rispetto a quelle osservate al basale e ad una dieta di controllo. Un semplice manipolazione alimentare di distribuzione carboidrati sembra avere ulteriori vantaggi rispetto a una dieta convenzionale perdita di peso in soggetti affetti da obesità. Potrebbe anche essere utile per le persone che soffrono di resistenza all'insulina e la sindrome metabolica. Sono necessarie ulteriori ricerche per confermare e chiarire i meccanismi con cui questo approccio dieta relativamente semplice migliora sazietà, portare a migliori risultati antropometrici, e raggiunge una migliore risposta metabolica, rispetto ad un approccio più convenzionale dietetico.

La medicina ha fatto così tanti progressi che ormai più nessuno è sano. Aldous Leonard Huxley | Veniamo tutti da ambienti diversi e iniziamo con alcune idee preconcette che potremmo abbandonare lungo la strada...


Quota
Eva
 Eva
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Post: 1905
26/11/2012 10:18 am  

Tempo fa lessi un articolo che diceva l'esatto contrario: carboidrati alla sera tutti stipati in grasso. Vorrei capire da dove escono queste ricerche...


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Tropico
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Post: 9776
26/11/2012 1:07 pm  

Se leggi bene, si parla di dieta ipocalorica, quindi la discrepanza potrebbe essere dovuta da quello, lo stesso studio è molto cauto e dice che i dati vanno confermati.

La medicina ha fatto così tanti progressi che ormai più nessuno è sano. Aldous Leonard Huxley | Veniamo tutti da ambienti diversi e iniziamo con alcune idee preconcette che potremmo abbandonare lungo la strada...


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Eva
 Eva
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Post: 1905
26/11/2012 2:29 pm  

Ah scusa perché nel titolo dice 'carboidrati mangiati prevalentemente di sera' ..... in un altro 'carboidrati di sera = tutto in grasso'
Insomma bisognerebbe valutare se a parità di calorie sia meglio carboidrati alla mattina o alla sera...


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Tropico
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Post: 9776
26/11/2012 3:02 pm  

Esatto, bisognerebe fare un confronto diretto con gruppo di controllo, allora le cose potrebbero apparire più chiare e significative 🙂

La medicina ha fatto così tanti progressi che ormai più nessuno è sano. Aldous Leonard Huxley | Veniamo tutti da ambienti diversi e iniziamo con alcune idee preconcette che potremmo abbandonare lungo la strada...


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Eva
 Eva
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Post: 1905
30/11/2012 10:00 am  

Anche parlando di IFasting bisognerebbe valutare se è meglio fare l'unico pasto della giornata alla mattina o a pranzo o a cena.


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Tropico
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Post: 9776
14/02/2013 7:04 pm  

Può la tempistica di quando si mangia, essere importante tanto quanto ciò che si mangia?
Questo è il primo studio su larga scala prospettico per dimostrare che i tempi dei pasti prevede la perdita di peso efficace
http://www.eurekalert.org/pub_releases/2013-01/bawh-ctt012413.php
Boston, MA-La maggior parte di perdita di peso piani intorno a un centro di equilibrio tra apporto calorico e il dispendio energetico. Tuttavia, una nuova ricerca ha messo in luce un nuovo fattore che è necessario per perdere peso: temporizzazione. I ricercatori del Brigham and Women Hospital (BWH), in collaborazione con l'Università di Murcia e Tufts University, hanno scoperto che non è solo ciò che si mangia, ma anche quando si mangia, che può aiutare con la perdita di peso regolamento.

"Questo è il primo grande studio prospettico per dimostrare che i tempi dei pasti prevede la perdita di peso efficace", ha detto Frank Scheer, PhD, MSc, direttore del programma Cronobiologia medica e neuroscienziato associato presso BWH, assistente professore di medicina alla Harvard Facoltà di Medicina, e autore senior di questo studio. "I nostri risultati indicano che mangiatori di ritardo visualizzato un più lento tasso di perdita di peso e perdita di peso significativamente inferiore rispetto mangiatori primi, suggerendo che l'intervallo tra i pasti di grandi dimensioni potrebbe essere un fattore importante in un programma di perdita di peso."

Per valutare il ruolo della distribuzione alimentare in perdita di peso efficace, i ricercatori hanno studiato 420 partecipanti allo studio in sovrappeso che hanno seguito da 20 settimane di perdita di peso programma di trattamento in Spagna. I partecipanti sono stati divisi in due gruppi: early-mangiatori e tardo-mangiatori, secondo l'auto-selezionato tempi del pasto principale, che in questa popolazione del Mediterraneo era il pranzo. Durante questo pasto, il 40 per cento delle calorie totali giornaliere sono consumati. Early-mangiatori pranzato in qualsiasi momento prima del 3 pm e tardo-mangiatori, dopo 15:00 Essi hanno scoperto che a tarda mangiatori perso peso notevolmente inferiore a quella precoce mangiatori, e visualizzato un ritmo molto più lento di perdita di peso. Late-mangiatori ha avuto anche una minore sensibilità all'insulina stimato, un fattore di rischio per il diabete.

I ricercatori hanno trovato che i tempi degli altri (più piccoli) pasti non ha giocato un ruolo nel successo di perdita di peso. Tuttavia, alla fine degli anni mangiatori-che ha perso meno peso anche consumato meno calorie durante la colazione e avevano più probabilità di saltare la prima colazione del tutto. Late-mangiatori ha avuto anche una minore sensibilità all'insulina stimato, un fattore di rischio per il diabete.

I ricercatori hanno anche esaminato altri fattori tradizionali che giocano un ruolo nella perdita di peso, come l'assunzione di calorie e delle spese, gli ormoni dell'appetito leptina e grelina, e la durata del sonno. Tra questi fattori, i ricercatori non hanno trovato differenze tra i due gruppi, suggerendo che il momento del pasto è stato un fattore importante e indipendente di successo perdita di peso.

"Questo studio sottolinea che i tempi di assunzione di cibo per sé può giocare un ruolo importante nella regolazione del peso", spiega Marta Garaulet, PhD, professore di Fisiologia presso l'Università di Murcia Spagna, e autore principale dello studio. "Nuove strategie terapeutiche dovrebbero includere non solo l'apporto calorico e distribuzione macronutrienti, come viene classicamente eseguita, ma anche i tempi di cibo."
# # #

Questa ricerca è stata sostenuta da sovvenzioni da Tomás Pascual e Pilar Gómez-Cuetara Fondazioni, governo spagnolo della scienza e dell'innovazione (BFU2011-24720), Séneca Fondazione da parte del governo di Murcia (15123/PI/10). National Heart, Lung, and Blood Institute sovvenzioni HL-54776, Istituto Nazionale del Diabete e digestive e malattie renali, il codice di autorizzazione DK075030 e da contratti 53-K06-5-10 e 58-1950-9-001 del Dipartimento dell'Agricoltura degli Stati Uniti di ricerca, e da National Heart, Lung, and Blood Institute concessione R01 HL094806, e Istituto Nazionale del Diabete e Malattie Digestive e Renali, concedere R21 DK089378.

Ospedale Brigham and Women (BWH) è un 793-letto filiale d'istruzione senza scopo di lucro della Harvard Medical School e membro fondatore di HealthCare Partners. BWH ha oltre 3,5 milioni di visite annuali, è il più grande centro di parto nel New England e impiega circa 15.000 persone. Preminenza medico del Brigham risale al 1832, ed oggi che la storia ricca di cura clinica è accoppiato con la sua leadership nazionale nella cura del paziente, miglioramento della qualità e iniziative per la sicurezza dei pazienti, e la sua dedizione alla ricerca, l'innovazione, coinvolgimento della comunità e l'educazione e la formazione della prossima generazione di operatori sanitari. Attraverso le indagini e la scoperta effettuata a suo Biomedical Research Institute (BRI), BWH è leader internazionale nella ricerca di base, clinica e traslazionale sulle malattie umane, che coinvolgono quasi 1.000 medici-ricercatori e scienziati di fama biomediche e docenti supportati da quasi $ 625 milioni di finanziamenti. BWH spinge continuamente i confini della medicina, tra cui lo sviluppo della sua eredità in trapianti d'organo eseguendo il trapianto prima faccia negli Stati Uniti nel 2011. BWH è anche sede di importanti studi sulla popolazione, punto di riferimento epidemiologici, compreso il Nurses 'e dei medici Studi sulla Salute, OurGenes e l'iniziativa di salute delle donne. Per ulteriori informazioni e risorse, si prega di visitare newsroom di BWH.

La medicina ha fatto così tanti progressi che ormai più nessuno è sano. Aldous Leonard Huxley | Veniamo tutti da ambienti diversi e iniziamo con alcune idee preconcette che potremmo abbandonare lungo la strada...


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Roberto
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Registrato: 8 anni fa
Post: 87
15/02/2013 2:33 pm  

Ciao
Io sono propenso, per mia esperienza personale quindi diciamo funziona per me, ad assumere carboidrati/amidi resistenti la sera. Seguo una low carb nella giornata ed assumo la sera carb in combinazione con verdure, cibi proteici/grassi (carne-pesce etc).
Dormo benissimo, con la low carb meno; come detto nella presentazione, sono dimagrito molto, peso stabile da piu di un anno, ed ho rimesso su massa.
I carb la sera dovrebbero anche migliorare la distribuzione della serotonina celebrale con conseguente miglior sintesi di melatonina.

Molti body bulders seguono una dieta che preveda carb la sera. C’e’un bell’ articolo di Anthony Colpo a proposito. Lo aggiungo in un altro post.

Inoltre ho trovato un sito molto interessante che non parla di dieta o di cibi si/no ma di quando consumarli. Beh penso che noi tutti sappiamo che la produzione di alcuni ormoni segue dei cicli specifici nel corpo umano, per es..cortisolo che aumenta la mattina poi decresce la sera( detto in modo maccheronico..non enro in dettagli) eche quindi questo posa influenzare l’utilizzo che se ne fa degli alimenti introdotti.
Molte diete si basano su questo. Anche la dieta di quel farmacista italiano..non ricordo il nome.

Ho trovato anche 3 recenti pubblicazioni ed uno studio effettuato in Israele:

Greater weight loss and hormonal changes after 6 months diet with carbohydrates eaten mostly at dinner.

Sofer S, Eliraz A, Kaplan S, Voet H, Fink G, Kima T, Madar Z.
Source
The Robert H. Smith Faculty of Agriculture, Food and Environment, Institute of Biochemistry and Food Science, The Hebrew University of Jerusalem, Rehovot, Israel.

Abstract

This study was designed to investigate the effect of a low-calorie diet with carbohydrates eaten mostly at dinner on anthropometric, hunger/satiety, biochemical, and inflammatory parameters. Hormonal secretions were also evaluated. Seventy-eight police officers (BMI >30) were randomly assigned to experimental (carbohydrates eaten mostly at dinner) or control weight loss diets for 6 months. On day 0, 7, 90, and 180 blood samples and hunger scores were collected every 4 h from 0800 to 2000 hours. Anthropometric measurements were collected throughout the study. Greater weight loss, abdominal circumference, and body fat mass reductions were observed in the experimental diet in comparison to controls. Hunger scores were lower and greater improvements in fasting glucose, average daily insulin concentrations, and homeostasis model assessment for insulin resistance (HOMA(IR)), T-cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) levels were observed in comparison to controls. The experimental diet modified daily leptin and adiponectin concentrations compared to those observed at baseline and to a control diet. A simple dietary manipulation of carbohydrate distribution appears to have additional benefits when compared to a conventional weight loss diet in individuals suffering from obesity. It might also be beneficial for individuals suffering from insulin resistance and the metabolic syndrome. Further research is required to confirm and clarify the mechanisms by which this relatively simple diet approach enhances satiety, leads to better anthropometric outcomes, and achieves improved metabolic response, compared to a more conventional dietary approach.

Altri due pubblicazioni
1) Cannon G. Dieting. Makes you fat? British Journal of Nutrition, 2005; 93: 569–570
2) Lowe MR, Timko CA. Dieting: really harmful, merely ineffective or actually helpful? British Journal of Nutrition, 2004; 92 (Suppl. 1): S19–S22.

you fat? British Journal of Nutrition, 2005; 93: 569–570

Qui di seguito il sito internet della Catalytic Longevity Carbohydrate-Concentration (CC) Diet:

http://catalyticlongevity.org/welcome-to-the-cc-carbohydrate-concentrated-diet57http://catalyticlongevity.org/welcome-to-the-cc-carbohydrate-concentrated-diet/

Versione inglese:

Welcome to the Catalytic Longevity Carbohydrate-Concentration (CC) Diet
Note that this rule doesn’t say anything about what you can or can’t eat. It also doesn’t say anything about how much you can eat. Rather the emphasis is on the timing of carbohydrate consumption — eating most of your carbohydrates over one relatively short time period of the day. You can eat a wider variety of food with the CC Diet compared to many other diet programs with the only requirement that you eat virtually all of your carbohydrates at one of your daily meals. You will find that this does not require as much discipline as you might expect because the low and steady insulin levels that you will have most of the time will moderate your appetite by unleashing your capacity to burn stored fat. In addition, your daily carbohydrate meal will tend to satiate your desire for carbs so you won’t feel deprived. The CC Diet provides enormous flexibility in the types of foods it allows. You don’t have to avoid fats or carbs or animal products. You can eat these foods — every day if you’d like — but there is a special rule for carbohydrates: you can’t eat them at every meal. Although the CC Diet requires that you concentrate your carbohydrate foods and eat them at one time of the day, it does not have to be the same time every day. It could be at lunch one day and at dinner the next depending on business, personal or social needs. Another advantage of the CC Diet is its lack of rigidity. It is not a diet which requires constant and daily compliance. We are all of us human and we all fall off the dietary wagon from time to time. Obviously the CC Diet will work best the more often it is followed but occasional lapses will not undo its effectiveness. This is in contradistinction to, say, a strict low carbohydrate diet where, if one deviates and eats some carbohydrates, ketosis ends and hunger returns.
What are Carbohydrates?

All of the calories you eat can be divided into three types: proteins, fats
and carbohydrates. Technically alcohol is a fourth, separate type of calorie, but for our purposes, since alcoholic beverages share the ability of carbohydrate to block fat burning. We will regard alcohol as a subtype of carbohydrate. Hence, on a CC diet your consumption of alcoholic beverages should be confined to the time period of your main carbohydrate meal — slightly before, slightly after, or during this meal.
Foods that come from animal sources such as meat, poultry and eggs tend to contain relatively small amounts of carbohydrates. Plant-derived foods such as vegetables, fruits and grains, on the other hand, are often rich in carbohydrates. Fruits tend to be high in carbohydrates. Vegetables that grow up above ground such as salad greens, broccoli, cauliflower, and kale tend to be low in carbohydrates while belowground vegetables such as potatoes, carrots, turnips, and parsnips are often high in carbohydrates. Carbohydrate foods are unique in that they have a tendency to raise blood glucose more quickly than other types of calories. Sustained elevations in the level of glucose in the bloodstream will raise insulin levels which in turn can create a host of problems including weight gain, diabetes, and an increased risk of cardiovascular disease. When carbohydrates are eaten at multiple occasions during the day, the body experiences multiple elevations in insulin which precludes fat-reduction —the exact opposite of what we are trying to achieve.
We need to consider the three broad categories of carbohydrates (and alcohol):
Sugars — also known as simple carbohydrates — typically raise blood glucose quickly
Starches — known as complex carbohydrates — can raise blood glucose quickly or slowly
Fiber — which is poorly digested or not just digested at all but has other health benefits — to not raise blood glucose
Alcohol — technically not a carbohydrate but raises blood glucose levels quickly similar to carbohydrates

Following the Diet

A recent scientific paper out of Israel by Dr. Sofer and colleagues showed that when most of the carbohydrates for the day are eaten at one meal (dinner), there was greater weight loss as well as other health benefits. This confirms an experiment done twenty years ago by Richard and Rachel Heller, authors of the Carbohydrate Addicts Diet, that showed the frequency with which carbohydrates were consumed during the day was the key. Many people will find it most convenient to have their carbohydrate meal for supper although you are free to switch it around and have your carbohydrate meal for breakfast or lunch. If you have a high carbohydrate breakfast — oatmeal, pancakes, pastries, bagels, fruit, etc. or a high carbohydrate lunch — sandwich with bread, pasta, potatoes, etc. — you will want to have low carbohydrate meals for the other two meals of the day. Carbohydrate Concentration means having the overwhelming majority of your carbs during one meal.

A Sample Day

Here is an example of a sample day where breakfast and lunch are low carb and supper is your carbohydrate meal.
Breakfast (Low Carb)
2 eggs with breakfast meat or
Protein shake prepared with no-added sugar soy milk or hemp milk
Lunch (Low Carb)
Salad with tuna, salmon, chicken and/or
Vegetable beef/chicken soup (no noodles)
Supper (Carbohydrate Concentrated)
Salad — ad lib
Protein (fish, poultry, meat) — ad lib
Vegetables — ad lib
Carbohydrates and alcohol — ad lib
Diet Tips
Weigh yourself every week. Aim to lose one or 2 pounds a week until you reach your goal weight. If you are not losing any weight (or gaining weight) there are several things you can do. Drink one or two glasses of water mixed with psyllium husk (available at health food stores) 15 to 30 minutes before beginning your carbohydrate meal. This will fill your stomach and likely reduce the calories you ingest with that meal. Eating a big low-calorie green salad before a main meal can be similarly helpful.. If you’re still not losing weight you mayl need to decrease the amount of carbohydrates you consume and you should consider choosing lower fat cuts of meat and reduced fat dairy products and minimizing use of added oils.

The Experiment

In order to demonstrate the effectiveness of carbohydrate concentration and the CC Diet — and to confirm its links to caloric restriction — we would like to invite you to participate in a simple experiment. We want to test the hypothesis that sustained adherence to carbohydrate concentration will not only cause you to lose weight but will enable you to achieve a permanent reduction in your daily calorie intake, even after your weight equibrates at a lower, healthier level — and without calorie counting.
If this is correct, not only will you achieve the many health benefits associated with greater leanness but you may also achieve some of the healthy-aging benefits associated with calorie restriction or intermittent fasting in animal studies..
In order to perform this experiment, we ask you to estimate your caloric intake averaged over three days, both before you begin your carbohydrate concentrated diet and after six months; of course, you can estimate it at any intervals you want on the diet. We suggest you keep a food diary and use the caloric figures found at the excellent website www.fatsecret.com. Then fill out the simple form including your height, weight, waist measurement, gender and year of birth. You can enter data as often as you like, but we would like to know how you are doing at 6 months. You can let us know using our form or ask us to remind you to let us know.
Height — in stocking feet
Weight — weigh yourself clothed without shoes and empty your pockets.
Waist Circumference — use a measuring tape to measure the circumference at the level of your umbilicus. Keep your abdomen relaxed and do not pull it in.

Why This Study is Important

The CC Diet is simple to follow, palatable and flexible. It allows you to eat the foods you love while shedding excess pounds and optimizing your health. The problem is that not enough people know about this diet. By participating in this simple experiment you will be able to help obtain the necessary scientific foundation to establish the CC Diet broadly.
In order to spread the message of the CC Diet we will need to enlist the support of conventional medical practitioners as well as public health officials. These people are scientists and scientific documentation will be required In order to convince them as to the value of this program. The rationale for most popular diets is based on little more than what is referred to as “anecdotal evidence.” They are based on anecdotes or individual stories rather than scientific studies. Most new diet programs rely on relatively thin evidence such as individual testimonials and before-and-after photos, as proof for how well they work.
The excellent scientific study by Sofer mentioned above confirms that distribution of carbohydrates is critical to many health parameters. But it was done under conditions of caloric restriction with both the CC diet group and the control group under substantial caloric restriction conditions. We want to establish, with our experiment, the additional fact that CC diets will lead to sustained reductions in weight and caloric intake without regard to enforced regimes or constant high degrees of will power. We consider our diet to be appetite-mediated rather than a white-knuckle diet.
The world is currently faced with epidemics of obesity and degenerative disease as well as a health budget crisis. These crises can’t wait. They threaten the health of both adults and children and have been directly linked to the ever-increasing expenditures on health care which currently consume 17 percent of our GNP.
The need for diet programs that can help is urgent. We invite you to try the Carbohydrate-Concentration Diet for yourself and help further this important work by participating in our experiment and tracking the changes in your own health.
P.S. We would also like to know — and you will find it interesting and easy to determine — what your degree of caloric restriction is compared to what we call “reference man”, a person of your same height, and with a similar exercise pattern, but with a body mass index (BMI) of 22. In others words, are you eating more or less than a person who is much like you but very fit in terms of body mass index. This can be easily computed at a website. For more background see the FAQ. The BMI of 22 was chosen as a standard because it is right in the middle of the “optimal” range for BMI.
Measuring your calorie consumption relative to “reference man” will help us compare how well this diet is working compared to caloric restriction regimes used in animal experimentation, or to the calorie restriction achieved by Okinawans in the middle years of the last century, and it will give you a better idea of the degree of calorie restriction-mediated health benefit you are likely to achieve with carb concentrated dieting. You can read more about this in different parts of the website, especially in the FAQs under Carb Concentrated diets.
We would also like you to save the blood reports from your doctor visits before and after you embark on carb concentrated dieting — so that, if we move forward with this project and decide to examine blood reports, and if you wanted to share them with us, we could use them. For the moment, however, we are not ready to make use of them.
Drafted by Dr. Terry Grossman as a more reader-friendly opening than had previously appeared on the website. This article included editing contributions from Stone and McCarty. For a historical summary of how the effort to advance this diet has proceeded so far, see Recent History of Low-Carb Dieting.

Sofer S et al. Greater Weight loss and hormonal changes after 6 months diet with carbohydrates eaten mostly at dinner. Obesity (Silver Spring). 2011 Apr 7. [Epub ahead of print]

Versione tradotta:

Si noti che questa regola non dice nulla su cosa si può o non può mangiare. Inoltre non dice nulla circa quanto si può mangiare. Piuttosto l'enfasi è sulla tempistica di consumo di carboidrati, mangiare la maggior parte dei vostri carboidrati in un periodo di tempo relativamente breve del giorno. Si può mangiare un'ampia varietà di prodotti alimentari con la dieta CC rispetto a molti altri programmi di dieta con l'unico requisito che si può mangiare praticamente tutti i vostri carboidrati presso uno dei vostri pasti giornalieri. Troverete che questo non richiede tanta disciplina come ci si potrebbe aspettare perché i livelli di insulina bassa e costante che si avrà la maggior parte del tempo modererà il vostro appetito da scatenare la vostra capacità di bruciare il grasso immagazzinato. Inoltre, il vostro pasto quotidiano di carboidrati tendono a saziare il vostro desiderio di carboidrati, quindi non si sentono depresse. La dieta CC fornisce enorme flessibilità nella tipologia dei cibi che permette. Non dovete evitare grassi o carboidrati o prodotti di origine animale. Si possono mangiare questi alimenti — ogni giorno se vuoi — ma c'è una regola speciale per carboidrati: si non può mangiare ad ogni pasto. Anche se la dieta CC è necessario concentrare i tuoi cibi carboidrati e mangiarli in una sola volta al giorno, non deve essere al tempo stesso ogni giorno. Potrebbe essere a pranzo un giorno a cena la prossima a seconda delle esigenze personali, sociali o di affari. Un altro vantaggio della dieta CC è la sua mancanza di rigidità. Non è una dieta che richiede la conformità costante e quotidiana. Siamo tutti noi umani e che tutti noi cadere il carro dietetico di volta in volta. Ovviamente la dieta CC funzionerà meglio più spesso è seguita ma decade occasionale non annullerà la sua efficacia. Questo è in contrapposizione a, diciamo, un rigoroso basso contenuto di carboidrati dieta dove, se uno si allontana e mangia alcuni carboidrati, chetosi finisce e fame restituisce.
Che cosa sono i carboidrati?
Tutte le calorie che si mangia può essere diviso in tre tipi: proteine, grassi e carboidrati. Tecnicamente l'alcool è una quarta, tipo separato di calorie, ma per i nostri scopi, poiché bevande alcoliche condividono la capacità di bloccare a bruciare i grassi carboidrati. Consideriamo alcool come un sottotipo di carboidrati. Quindi, su una dieta CC il tuo consumo di bevande alcoliche dovrebbe limitarsi al periodo che va dal vostro pasto principale carboidrato — leggermente prima, poco dopo, o durante il pasto.
Alimenti che provengono da fonti animali, come carne, pollame e uova tendono a contenere relativamente piccole quantità di carboidrati. Alimenti vegetali come verdura, frutta e cereali, d'altra parte, spesso sono ricchi di carboidrati. Frutti tendono ad essere ad alto contenuto di carboidrati. Verdure che crescono sopra terra come insalate, broccoli, cavolfiore e cavolo tendono ad essere a basso contenuto di carboidrati mentre belowground verdure come patate, carote, rape e Pastinaca sono spesso ad alto contenuto di carboidrati. Carboidrati cibi sono unici in quanto hanno la tendenza ad alzare la glicemia più rapidamente di altri tipi di calorie. Elevazioni sostenute del livello di glucosio nel sangue aumenterà i livelli di insulina che a sua volta possono creare una serie di problemi tra cui un aumento del rischio di malattie cardiovascolari, diabete e aumento di peso. Quando carboidrati si mangiano, in più occasioni durante il giorno, il corpo vive più elevazioni di insulina che impedisce la riduzione del grasso — l'esatto opposto di ciò che stiamo cercando di raggiungere.
Abbiamo bisogno di prendere in considerazione le tre grandi categorie di carboidrati (e alcool):
Zuccheri — conosciuto anche come carboidrati semplici — tipicamente alzare la glicemia rapidamente
Amidi e fecole — conosciuto come carboidrati complessi — può alzare la glicemia rapidamente o lentamente
Fibra — che è mal digerito o non appena digerito affatto ma ha altri benefici per la salute, per non generare glucosio nel sangue
Alcol — tecnicamente non un carboidrato ma genera livelli di glucosio nel sangue rapidamente simili ai carboidrati
Seguendo la dieta
Un recente documento scientifico fuori Israele da Dr. Sofer e colleghi hanno mostrato che quando la maggior parte dei carboidrati per il giorno si mangiano in un pasto (cena), c'era una maggiore perdita di peso, nonché di altri benefici per la salute. ciò conferma un esperimento fatto vent'anni fa da Richard e Rachel Heller, autori di carboidrati dieta tossicodipendenti, che ha mostrato la frequenza con cui i carboidrati sono stati consumati durante il giorno è stata la chiave. Molte persone si trovano più conveniente avere loro pasto di carboidrati per cena anche se si è liberi di passare intorno e avere il vostro pasto di carboidrati per la colazione o il pranzo. Se si dispone di una colazione di carboidrati ad alta — farina d'avena, frittelle, dolci, bagel, frutta, ecc., o un pranzo di carboidrati alto — sandwich con pane, pasta, patate, ecc. — si desidera avere pasti a basso contenuto di carboidrati per gli altri due pasti della giornata. Concentrazione di carboidrati significa avere la stragrande maggioranza dei vostri carboidrati durante un pasto.


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Tropico
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Post: 9776
15/02/2013 2:49 pm  

Anche Matt Stone è dell'avviso di distribuire i carboidrati la sera se non erro, appunto per modulare la serotonina.

La medicina ha fatto così tanti progressi che ormai più nessuno è sano. Aldous Leonard Huxley | Veniamo tutti da ambienti diversi e iniziamo con alcune idee preconcette che potremmo abbandonare lungo la strada...


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Roberto
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Post: 87
15/02/2013 4:32 pm  

Anche Matt Stone è dell'avviso di distribuire i carboidrati la sera se non erro, appunto per modulare la serotonina.

Ciao
se non ricordo male Matt Stone c'e' l'ha a morte con la serotonina. o sbaglio?


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Tropico
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Post: 9776
15/02/2013 4:37 pm  

Se è d'accordo con le idee di Ray Peat probabilmente sì, ma non sono sicuro che sia tout court contro la serotonina.

La medicina ha fatto così tanti progressi che ormai più nessuno è sano. Aldous Leonard Huxley | Veniamo tutti da ambienti diversi e iniziamo con alcune idee preconcette che potremmo abbandonare lungo la strada...


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Eva
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Post: 1905
15/02/2013 8:05 pm  

Io penso che il pasto serale e la seguente digestione dia fastidio alla melatonina e di conseguenza al sonno.


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Tropico
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Post: 9776
16/02/2013 6:28 pm  

Dia fastidio in che senso? E' risaputo che andare a dormire con la fame tutto aiuta tranne che il sonno, ma aumenta l'allerta, l'esser vigili.
Poi ci sono tante variabili personali ma in linea di massima direi che è così.

La medicina ha fatto così tanti progressi che ormai più nessuno è sano. Aldous Leonard Huxley | Veniamo tutti da ambienti diversi e iniziamo con alcune idee preconcette che potremmo abbandonare lungo la strada...


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Roberto
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Post: 87
18/02/2013 11:09 am  

Io penso che il pasto serale e la seguente digestione dia fastidio alla melatonina e di conseguenza al sonno.

Ciao Eva,
Scusa ma in che senso?
La melatonina non ha niente a che fare con la digestione. Ha molto a che fare con il tipo di alimenti ingeriti e la loro successiva utilizzazione.
Mangiare carne di pollo/tacchino ricchi di un aminoacido triptofano, stimolano ( la dico semplice) la capacita di questo aminoacido di penetrare attraverso la corteccia celebrale, nel cervello con conseguente stimolazione della fase di trasformazione del triptofano in serotonina ...e di notte in melatonina. In America lo sanno bene..per ThanksGiving mangiano tacchino e poi hanno tutti sonnolenza...si chiama Turkey drowsiness (sonnolenza da tacchino).
Come dicevo sopra e come ribadito da Tropico, e'molto personale. Ognuna reagisce in modo piu o meno diverso...sembra strano ma e'cosi.

In generale un pasto di carboidrati dovrebbe stimolare/favorire la captazione del triptofano nel cervello e la conversione in serotonina...quindi melatonina.

Il digiuno/la fame come diceva Tropico attiva molti ormoni che contrastano il sonno.

Non domentichiamo inoltre che la maggior parte della serotonina/melatonina viene prodotta non nel cervello ma nell'intestino...ma questa non puo oltrepassare la barriera celebrale.

Ciao
Roberto


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Eva
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Post: 1905
18/02/2013 12:53 pm  

Tempo fa avevo letto il libro 'La dieta Ormonale' di Hertoghe dove diceva che il pasto aumenta la temperatura e questo potrebbe ritardare la produzione di Melatonina che avviene con una temperatura bassa.
Inoltre è consigliato mangiare e aspettare almeno 2 ore prima di coricarsi.


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Roberto
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Post: 87
18/02/2013 3:06 pm  

Ciao Eva,
Penso tu ti riferisca a :

"If you feel you must eat, avoid bedtime snacks that are high in sugar or simple carbohydrates. Carbohydrate-rich snacks such as breads, cereals, muffins, cookies or other baked goods raise blood sugar levels for a short time, causing them to fall later. When there is a drop in blood sugar, adrenalin, glucagon, cortisol and growth hormone are released to regulate blood glucose levels. These hormones can be stimulating to the brain causing you to awaken and to experience difficulties falling back asleep.
• Eating before bed also raises your body temperature which interferes with the release of recuperative hormones while we sleep and interferes with weight loss.
• Try not to eat for at least two hours before going to bed. If you do need to eat something, have a snack that contains protein such as a few almonds and half of an apple.
• Protein provides a source of the amino acid tryptophan. The body converts tryptophan to serotonin and melatonin, hormones that are important for sleep. The sugars from the fruit may help the tryptophan reach the brain more easily."

Tradotto

"Se ti senti che devi mangiare, evitare spuntini a nanna che sono ad alti contenuto di zuccheri o carboidrati semplici. Snack ricchi di carboidrati come pane, cereali, muffin, biscotti o altre prodotti da forno sollevare glicemie per breve tempo, causando loro di cadere più tardi. Quando c'è un calo di zuccheri nel sangue, adrenalina, glucagone, cortisolo e ormone della crescita vengono rilasciati per regolare i livelli di glucosio nel sangue. Questi ormoni possono essere stimolanti per il cervello causando a risvegliare e a incontrare difficoltà ad addormentarsi nuovamente.
• Mangiare prima di dormire anche solleva la temperatura corporea che interferisce con il rilascio di ormoni recuperativi mentre dorme e interferisce con la perdita di peso.
• Cercare di non mangiare per almeno due ore prima di andare a letto. Se hai bisogno di mangiare qualcosa, fare uno spuntino che contiene proteine come poche mandorle e metà di una mela.
• Proteina fornisce una fonte dell'aminoacido triptofano. Il corpo converte il triptofano in serotonina e melatonina, gli ormoni che sono importanti per un sonno. Gli zuccheri del frutto possono aiutare il triptofano raggiungono il cervello più facilmente.

Queste sono linee generali e non so neppure chi le abbia scritte. Erthog ha le sue idee..non sempre convalidate.

Qui di seguito un articolo a proposito.
La versione tradotta.

I pasti di carboidrati ad alto indice glicemico-indice accorciare insorgenza di sonno 1, 2,3

Ahmad Afaghi, Helen o ' Connor e Chin Chow Moi + autore affiliazioni
1Da la scuola di esercizio e Sport Science, facoltà di Health Sciences, University of Sydney, Sydney, Australia

Sfondo: Assunzione di carboidrati alimentari ha dimostrato di aumentare la concentrazione plasmatica di triptofano, un precursore della serotonina e l'agente che induce il sonno.

Obiettivo: Per indagare il ruolo dei carboidrati nell'induzione del sonno, abbiamo esplorato l'effetto dell'indice glicemico (GI) e l'ora del pasto il sonno in volontari sani.

Design: Abbiamo confrontato l'effetto dell'alta e bassa-GI carbohydrate–based pasti ingeriti 4 ore prima di coricarsi sulla qualità del sonno. Abbiamo inoltre valutato l'effetto dei tempi di pasti ad alto-GI (4 h rispetto a 1 h) sulla qualità del sonno. Dodici uomini sani (età 18-35 y) sono stati amministrati standard, isocaloric (3212 kJ; 8% dell'energia come proteina, 1,6% dell'energia come grasso e 90.4% di energia sotto forma di carboidrati) pasti di entrambi Mahatma (basso IG = 50) o gelsomino (alto IG = 109) 4 h di riso prima di loro coricarsi usuale. In un'altra occasione, il pasto di alta-GI è stato dato 1 h prima di coricarsi. I partecipanti hanno subito una notte di familiarizzazione seguita da test di 3 notti in ordine casuale 1 wk apart.

Risultati: Una significativa (P = 0.009) riduzione della latenza di insorgenza di sonno medio (± SD) (SOL) è stato osservato con un alto-GI (9.0 ± 6,2 min) rispetto ad un basso-GI (17,5 ± 6,2 min) pasto consumato 4 ore prima di coricarsi. Il pasto di alta-GI dato 4 ore prima di coricarsi ha mostrato un SOL significativamente ridotto rispetto al pasto stesso dato 1 h prima di coricarsi (9.0 ± 6,2 min rispetto ai 14,6 ± 9,9 min; P = 0.01). Sono stati osservati effetti su altre variabili di sonno.

Conclusioni: Abbiamo dimostrato che un pasto di alta-GI basata su carboidrati ha provocato un accorciamento significativo del SOL in traversine sani rispetto ad un pasto di basso-GI e fu più efficaci quando consumato 4 ore prima di coricarsi. La rilevanza di queste scoperte per persone con disturbi del sonno dovrebbe essere determinata in future sperimentazioni.
Carbohydratesglycemic indexsleep qualitysleep tempi
Precedente SectionNext SectionINTRODUCTION

Le difficoltà di sonno comuni comprendono sonno iniziazione e manutenzione. Secondo The Gallup Organization, 49% degli adulti negli Stati Uniti non dormo bene per ≥ 5 notti/mo, imbracciarono % hanno insonnia intermittente e 10-15% hanno difficoltà di sonno a lungo termine (1). In Australia, un sondaggio ha riportato una prevalenza di insonnia del 17% negli uomini e il 25% delle donne in una comunità urbana (2).
Le attuali opzioni di trattamento per l'insonnia sono la farmacoterapia e terapia cognitivo-comportamentale. Trattamenti sono considerati efficaci se accorciare la latenza di insorgenza di sonno (SOL) o aumentare il tempo di sonno totale di 30 min (3). Terapia cognitivo-comportamentale è considerata la migliore pratica. Altri rimedi popolari usati per trattare problemi di sonno includono sedativi prescritti e tranquillanti, estratti di erbe e farmaci gratuiti, massaggi e tecniche di rilassamento, attività fisica regolare ed evitare stimolanti come la caffeina prima di dormire.
Temporizzazione (4, 5) e macronutriente contenuto (6-9) dei pasti sono noti per influenzare il sonno. Un pasto consumato vicino al momento di coricarsi è associato a disturbi del sonno (4). Un certo numero di macronutrienti influenza il sonno attraverso il triptofano (Trp), che serve come un precursore della serotonina cerebrale, un agente che induce il sonno (10, 11). Un fattore che favorisce l'entrata di Trp nel cervello è la sua concentrazione plasmatica rispetto a quello degli altri grandi neutri amminoacidi (LNAAs: tirosina, fenilalanina, leucina, isoleucina, valina e metionina) (12). È ormai noto che carboidrati di alto-indice glicemico (GI) hanno la capacità di aumentare il rapporto Trp a LNAAs (Trp:LNAA) che circolavano tramite un'azione diretta di insulina, che favorisce un assorbimento muscolare selettivo di LNAAs (13). Così, un pasto di alta-GI dovrebbe favorire il sonno tramite un aumento nel cervello Trp e serotonina come il plasma Trp:LNAA aumenta (12). Esso dovrebbe inoltre che un pasto contenente un alto contenuto proteico, che contribuisce meno Trp al sangue circolante confrontato con gli altri LNAAs (12) e quindi un plasma inferiore Trp:LNAA, ridurrebbe la serotonina. Funzione di serotonina può essere misurata indirettamente attraverso i cambiamenti nelle concentrazioni di melatonina, perché la serotonina è un prodotto intermedio nella produzione di melatonina, un ormone pineale (14). 6-Hydroxymelatonin urinaria solfato, un prodotto finale stabile di melatonina, è spesso usato come una misura di surrogato di melatonina, data la loro relazione lineare (14).
Pertanto, l'obiettivo del presente studio era di indagare il ruolo dei carboidrati nell'indurre il sonno e in particolare l'effetto di GI su sonno in traversine sani. Abbiamo ipotizzato che basata su carboidrati alto-rispetto al basso-GI pasti ingeriti 4 h prima di coricarsi migliorerebbe la qualità del sonno a causa di una maggiore risposta insulinica e che i tempi del pasto alto-GI (4 h rispetto a 1 h) b

Come potrai notare nella letteratura a fine articolo (inglese) ci sono molti articoli interessanti.

Versione completa

© 2007 American Society for Clinical Nutrition
High-glycemic-index carbohydrate meals shorten sleep onset 1,2,3
1. Ahmad Afaghi,
2. Helen O'Connor, and
3. Chin Moi Chow
+ Author Affiliations
1. 1From the School of Exercise and Sport Science, Faculty of Health Sciences, The University of Sydney, Sydney, Australia

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Abstract
Background: Dietary carbohydrate intake has been shown to increase the plasma concentration of tryptophan, a precursor of serotonin and sleep-inducing agent.
Objective: To investigate the role of carbohydrate in sleep induction, we explored the effect of glycemic index (GI) and meal time on sleep in healthy volunteers.
Design: We compared the effect of high- and low-GI carbohydrate–based meals ingested 4 h before bedtime on sleep quality. We also evaluated the effect of the timing of high-GI meals (4 h compared with 1 h) on sleep quality. Twelve healthy men (aged 18-35 y) were administered standard, isocaloric (3212 kJ; 8% of energy as protein, 1.6% of energy as fat, and 90.4% of energy as carbohydrate) meals of either Mahatma (low GI = 50) or Jasmine (high GI = 109) rice 4 h before their usual bedtime. On another occasion, the high-GI meal was given 1 h before bedtime. The participants underwent a familiarization night followed by 3 test nights in random order 1 wk apart.
Results: A significant (P = 0.009) reduction in the mean (±SD) sleep onset latency (SOL) was observed with a high-GI (9.0 ± 6.2 min) compared with a low-GI (17.5 ± 6.2 min) meal consumed 4 h before bedtime. The high-GI meal given 4 h before bedtime showed a significantly shortened SOL compared with the same meal given 1 h before bedtime (9.0 ± 6.2 min compared with 14.6 ± 9.9 min; P = 0.01). No effects on other sleep variables were observed.
Conclusions: We showed that a carbohydrate-based high-GI meal resulted in a significant shortening of SOL in healthy sleepers compared with a low-GI meal and was most effective when consumed 4 h before bedtime. The relevance of these findings to persons with sleep disturbance should be determined in future trials.
Carbohydrates
glycemic index
sleep quality
sleep timing
Previous SectionNext Section
INTRODUCTION
Common sleep difficulties include sleep initiation and maintenance. According to The Gallup Organization, 49% of adults in the United States do not sleep well for ≥5 nights/mo, 10–40% have intermittent insomnia, and 10–15% have long-term sleep difficulties (1). In Australia, a survey reported an insomnia prevalence of 17% in men and 25% in women in an urban community (2).
The current treatment options for insomnia are pharmacotherapy and cognitive behavioral therapy. Treatments are considered effective if they shorten sleep onset latency (SOL) or increase total sleep time by 30 min (3). Cognitive behavioral therapy is considered the best practice. Other popular remedies used to treat sleep difficulties include prescribed sedatives and tranquilizers, herbal extracts and complimentary medicines, massage and relaxation techniques, regular physical activity, and avoidance of stimulants such as caffeine before sleeping.
Both the timing (4, 5) and macronutrient content (6-9) of meals are known to influence sleep. A meal consumed close to bedtime is associated with sleep disturbance (4). A number of macronutrients influence sleep through tryptophan (Trp), which serves as a precursor for brain serotonin, a sleep-inducing agent (10, 11). A factor that promotes the entry of Trp into the brain is its plasma concentration relative to that of the other large neutral amino acids (LNAAs: tyrosine, phenylalanine, leucine, isoleucine, valine, and methionine) (12). It is now known that high-glycemic-index (GI) carbohydrates have the ability to increase the ratio of circulating Trp to LNAAs (Trp:LNAA) via a direct action of insulin, which promotes a selective muscle uptake of LNAAs (13). Thus, a high-GI meal would be expected to promote sleep via an increase in brain Trp and serotonin as the plasma Trp:LNAA increases (12). It would also be expected that a meal containing a high protein content, which contributes less Trp to the circulating blood compared with the other LNAAs (12) and thus a lower plasma Trp:LNAA, would reduce serotonin. Serotonin function may be measured indirectly through changes in melatonin concentrations, because serotonin is an intermediary product in the production of melatonin, a pineal hormone (14). Urinary 6-hydroxymelatonin sulfate, a stable end product of melatonin, is often used as a surrogate measure of melatonin, given their linear relation (14).
Therefore, the aim of the present study was to investigate the role of carbohydrate in inducing sleep, and specifically the effect of GI on sleep patterns in healthy sleepers. We hypothesized that carbohydrate-based high- compared with low-GI meals ingested 4 h before bedtime would improve sleep quality because of a greater insulin response and that the timing of the high-GI meal (4 h compared with 1 h) before bedtime would also influence sleep quality.
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SUBJECTS AND METHODS
Subjects
Twelve healthy, young (aged 18–35 y), normal weight (body mass index: 18.5–25 kg/m2) men were recruited from among 50 subjects screened. Subjects were excluded if they had a self-reported current or past history of significant medical, psychiatric, or sleep disorders (nocturnal eater inclusive), used prescribed medication (including sedatives or antidepressants) or recreational drugs, or regularly had an alcohol intake >20 g (2 drinks)/d on average, or exercised vigorously 24 h before a sleep study. The study was approved by the Human Research Ethics Committee of Sydney University.
Procedure
All subjects completed a medical evaluation questionnaire and a 2-wk sleep diary before undergoing a familiarization night of full sleep study (polysomnography). The subjects were given each of the following 3 standardized meals in a randomized order 1 wk apart: a high-GI meal administrated 4 h before their usual bedtime, a high-GI meal administrated 1 h before their usual bedtime, and a low-GI meal ingested 4 h before their usual bedtime. On the testing day, the subjects fasted for 5 h before the standardized meal. After voiding, the subjects ate their meals in 15 min. Finger prick blood samples for glucose analysis (with the use of a glucometer, Medisense Optium; Abott Laboratories, MediSense Products, Bedford, MA) were collected before the meal (baseline) and at 15, 30, 45, 60, 90, and 120 min after the high- and low-GI meals ingested 4 h before bedtime, and after high-GI meal ingested 1 h before bedtime (samples were collected at 15, 30, and 45 min before bedtime).
Urine for analysis of 6-sulfatoxymelatonin (6-SM) was collected in 2 parts: after the meal until bedtime and bedtime through to the next morning. The volume of collected urine and time period were recorded, and 2 aliquots of each volume were stored frozen (−80 °C) for 6-SM analysis with a commercially available enzyme-linked immunoassay kit (ImmunoBiological Laboratories, Hamburk, Germany). A 10-cm visual analogue scale (VAS) was checked on a 4-point scale, from extremely hungry to extremely full, before and after each meal to assess the subjects' hunger and fullness. Subjective feelings of sleepiness were assessed at 30 min and at 1, 2, 3, and 4 h after each meal by marking appropriately on a 10-cm 4-point sleepiness scale VAS from zero (“not at all sleepy”) to +3 (“very sleepy”). The validity and reliability of this VAS sleepiness scale has been shown (15).
Meals
Standard isocaloric meals (3212 kJ; 8% of energy as protein, 1.6% of energy as fat, and 90.4% of energy as carbohydrate) included 600 g steamed rice (200 g raw) and 200 g steamed vegetables in tomato puree. The rice was either low (Mahatma long grain, Riviana Foods Inc, Sydney Australia; GI = 50) or high (Jasmine aromatic long grain; Riviana Foods Inc; GI = 109) GI (16). The glycemic load (GL) was calculated as (GI/100) × g available carbohydrate. A higher GL meal results in a greater elevation of blood glucose and insulin (16). The GL was 81.3 and 175 for the low- and high-GI meals, respectively.
Polysomnographic recording
A full polysomnography with an international 10–20 electrode placement (C3/A2, O2/A1) (17) and respiratory recordings (to exclude sleep breathing disorders) and leg electromyogram (to exclude limb movement disorders; Compumedics S-series Sleep system; Compumedics Ltd, Melbourne, Australia) were applied on the familiarization night. Subsequently on study nights, sleep electroencephalogram, electrooculogram, and electromyogram only were recorded. The sleep studies were scored by an expert sleep physiologist (CMC) who was blinded to the treatments. Sleep recordings were evaluated for variables of total sleep time (TST); sleep efficiency (SE); SOL; arousal index; non–rapid eye movement sleep stages 1, 2, 3, and 4; and rapid eye movement (REM) sleep.
Statistics
The sample size was calculated based on effect sizes obtained for sleep latency (0.82) and sleep efficiency (2.18) powered at 80% and an alpha of 5% in an intervention study of tryptophan-free drink on sleep (18). We estimated that an effect size of 1.6 and a calculated sample size of 12 were appropriate for our crossover design study. Data were inspected for normality of distribution before use of parametric statistics with SPSS version 13 (SPSS Inc, Cary, NC). Data are reported as means ± SDs. Sleep indexes were analyzed by repeated-measures analysis of variance (ANOVA) and test of within-subjects contrasts to determine the effect of the 3 treatments on sleep. Data obtained for sleepiness and hunger or fullness by VAS were analyzed by paired Student's t test. Urine 6-SM was analyzed by repeated-measures ANOVA to examine the effects of the high- and low-GI meals given 4 h before bedtime. The blood glucose response was analyzed by using the area under the curve (AUC) and paired Student's t test. The relation between blood glucose AUC and SOL was analyzed via Pearson's correlation coefficient for both the high- and low-GI (4 h) meals. The repeated-measures ANOVA was used to test for the effect of meal type, time post-meal, and their interaction on blood glucose measured at baseline and at 15, 30, 45, 60, 90, and 120-min intervals after eating.
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RESULTS
Sleep variables
Sleep was ad libitum, with usual bedtime falling between 2145 to 0030 [x̄ (±SD) time: 2330 h ± 52 min], and the timing was consistent for each subject for each study night. The mean values for all sleep variables are shown in Table 1⇓. SOL was significantly different between the low- and high-GI meals given 4 h before bedtime and between the high-GI meal given 4 h and 1 h before bedtime. Mean SOL was reduced by 8.5 ± 9.3 min after the high-GI meal compared with the low-GI meal given 4 h before bedtime (P = 0.009) and by 5.6 ± 6.3 min when the high-GI meal was eaten 4 h before bedtime compared with 1 h (P = 0.01). Note that all subjects showed a reduction in SOL except for one (who showed an increase) (Figure 1⇓). The other sleep indexes were not significantly different between meals of varying GI or with respect to the timing of the high-GI meal ingestion (Table 1⇓).

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FIGURE 1.
Comparison of sleep onset latency (SOL) between the high-glycemic-index (GI) meal ingested 1 h or 4 h before bedtime and the low-GI meal ingested 4 h before bedtime. PC, subject who showed an inappropriate trend in the SOL for the 3 meals. The mean (±SD) SOLs for the low-GI meal given 4 h before usual bedtime and the high-GI meals given 4 h and 1 h before the usual bedtime were 17.5 ± 6.2, 9.0 ± 6.2, and 14.6 ± 9.9 min, respectively (n = 12). The SOL was significantly shortened after the high-GI meal compared with the low-GI meal when given 4 h before usual bedtime (P = 0.009). When considering the timing of the high-GI meals, the SOL of the meal ingested 4 h before bedtime was significantly shortened compared to the meal ingested 1 h before bedtime, P = 0.01 (repeated-measures ANOVA).
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TABLE 1
Effect of the glycemic index (GI) and timing of meals on sleep1
Sleepiness scale
A rating of 2.0 corresponded to “sleepy” on the VAS scale. The greatest postprandial differences of sleepiness rating following the test meals occurred at bedtime. The subjects tended to feel sleepier and less awake after the high-GI meal ingested 4 h before bedtime (2.3 ± 0.6) than they did after the low-GI meal ingested 4 h before bedtime (2.1 ± 0.3, P = 0.1). However, they were significantly sleepier after the high-GI meal ingested 4 h before bedtime than after that ingested 1 h before bedtime (1.9 ± 0.5, P = 0.04).
Hunger and fullness scale
The VAS rating of hunger or fullness confirmed that the large rice serving given was adequate so that subjects were not hungry after the meal. Respective ratings immediately after the meal and at bedtime were 3.21 and 2.17 for the low-GI meal ingested 4 h before bedtime; 3.17 and 2.13 for high-GI meal ingested 4 h before bedtime; and 3.17 and 2.25 for the high-GI meal ingested 1 h before bedtime. On a 4-point scale, a rating of 3 indicates that the subject feels “full” after the meal. These ratings were not significantly different between the high- and low-GI meals ingested 4 h before bedtime (P = 0.67 and P = 0.72 after the meal and at bedtime, respectively), between the high-GI meals ingested 4 h and 1 h before bedtime (P = 1.0 and P = 0.28 after the meal and at bedtime, respectively), and between the low-GI meal ingested 4 h before bedtime and the high-GI meal ingested 1 h before bedtime (P = 0.72 and P = 0.17 after the meal and at bedtime, respectively).
6-SM analysis
The evening collection concentration of 6-SM, a metabolite of melatonin, showed no significant differences between the high-GI meal ingested 4 h before bedtime (661.8 ± 228.1 ng/h; CV = 34%), the high-GI meal ingested 1 h before bedtime (556.4 ± 209.8 ng/h; CV = 37%; P = 0.3), and the low-GI meal ingested 4 h before bedtime (602.4 ± 208.8 ng/h; CV = 34%; P = 0.5). Higher concentrations of 6-SM, as expected, were seen for the night collection (1783.6 ± 618.8 ng/h; CV = 34%; and 1718.5 ± 484.0 ng/h; CV = 28%; P = 0.6, and 1571.6 ± 482.6 ng/h, CV% = 30%; P = 0.2, respectively).
Blood glucose
The blood glucose response to both the high- and low-GI meals is shown in Figure 2⇓. Blood glucose rose to a peak at ≈30 and 45 min after meal ingestion, followed by a steady decrease. The repeated-measures ANOVA confirmed that the blood glucose profiles over time differed between the 2 meal types (P = 0.001 for the group by time interaction). The AUC was significantly greater for the high-GI (336.2 ± 61.9) than for the low-GI (237.1 ± 69.3) meal (Student's t test, P = 0.009). The blood glucose response to ingestion of a high-GI meal 1 h before bedtime was similar to that observed after ingestion of a high-GI meal 4 h before bedtime for time points up to 45 min. No relation was observed between the subjects' glucose AUC and their SOL either for the high-GI meal (r = 0.2, P = 0.6) or the low-GI meal (r = −0.3, P = 0.5).

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FIGURE 2.
Blood glucose response to meals with a high (▪) and low (•) glycemic index (GI) given 4 h before bedtime. The interaction of meal type and time after meal ingestion was significant (P = 0.001). Significant differences between the area under the curves for the glucose response to the high- and low-GI meals were observed: 336.2 ± 61.9 and 237.1 ± 69.3, respectively (P = 0.009; n = 8).
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DISCUSSION
To our knowledge, this is the first study that showed a significant effect of glycemic index on SOL. We found that a high-GI meal given 4 h before bedtime significantly shortened SOL by 48.6% compared with a low-GI meal given 4 h before bedtime or by 38.3% compared with the same meal given 1 h before bedtime. If replicated in a cohort with sleep disturbance, such a nonpharmacologic approach to the management of insomnia may prove valuable, given the notorious side effects of medications used to achieve this outcome (19).
It is worth noting that one subject (PC) (Figure 1⇑) showed an inappropriate trend in the SOL for the 3 meals. Further examination of his sleep data revealed a reduction in REM sleep, a delay in ROL, and an increase in stage 2 after both high-GI (4 h and 1 h) meals. These data contrasted those for the mean values obtained for the other 11 subjects. As an elite cyclist, PC claimed to have ceased all exercise for ≥24 h before each of the sleep studies, and thus fulfilled inclusion criteria for the present study. Although inappropriate to delete PC from the data, it is known that changes to sleep variables are associated with acute strenuous exercise (20). In the case of PC, 24 h cessation of exercise may have been insufficient to normalize sleep indexes.
The mechanism by which a high-GI carbohydrate meal shortens SOL is currently unknown, but it is possible that the high-GI meal works through an increased plasma concentration of insulin and Trp to large neutral amino acid ratio (Trp:LNAA) and its ability to compete for entry into the brain with other LNAAs. The entry of Trp into the brain is linked to its concentration relative to other LNAAs and the main determinant of brain serotonin concentration is a high plasma Trp:LNAA (21). It is now known that the plasma Trp:LNAA is affected by both dietary carbohydrates and dietary protein (12, 22).
Once in the brain, Trp is converted to serotonin, which is also spontaneously produced in the raphe system of the brainstem (10). Serotonin is necessary for normal sleep of mammals (10). Ingestion of L-Trp significantly reduces the SOL of insomniacs and that of healthy sleepers (10). Indeed, several studies and review articles of the effect of Trp on sleep (4, 11, 23) support the notion that Trp reduces SOL without affecting other sleep variables. Hartmann (11) revealed a 45% reduction in SOL after Trp loading compared with placebo. These findings are consistent with our data from the high-GI meal ingested 4 h before bedtime, which showed a SOL reduction of 48.6% compared with the low-GI meal ingested 4 h before bedtime. The VAS data also lent support for the SOL findings. The subjects were significantly sleepier after the high-GI meal ingested 4 h before bedtime than after that ingested 1 h before bedtime, and there was a trend toward being sleepy in a comparison between the high- and low-GI meals ingested 4 h before bedtime.
A high-GI carbohydrate meal hastens glucose entry into the blood and facilitates a greater insulin response in healthy subjects (24, 25), in noninsulin dependent diabetic subjects (26), and in obese insulin-resistant subjects (27). In response to an increasing plasma glucose concentration, insulin mediates the uptake of LNAAs into muscle, but not Trp that is largely bound to plasma albumin (25, 28), thus leaving a high Trp:LNAA. In our study, although we did not measure the insulin response, we provided evidence for a significantly higher blood glucose response after a high-GI meal compared with the low-GI meal (Figure 2⇑). The GL of the high-GI meal of 175 in the present study was substantial compared with 81.3 for the low-GI meal. The higher the GL, the greater the insulinogenic effect (16). Meals with a GL >20 are considered to be high, and over a day a GL of 120 is rated as high (29). Hence, the GL of the high-GI meal was 1.5 times higher than the GI most persons would consume in an entire day. The test meals were almost entirely composed of rice and had low protein content. High protein content would have confounded the GI effects seen in the present study. Even the low-GI meal had a GL of 81.3, which is still high for a meal and around the cutoff (GL < 80/d is considered low) between high and low over a day. In the future, the effect of mixed meals with high and low GI or GL would be important, because regular consumption of meals with such a high GL would not be suitable for persons with diabetes or obesity (30-32).
The study conducted by Lyons and Truswell (25) showed that carbohydrates with a high GI induce a greater increase in the plasma Trp:LNAA than do carbohydrates with a low GI. Accordingly, Trp entry into the brain in response to a higher Trp:LNAA thus would predict a greater synthesis of serotonin. Indeed, it has been shown that a high Trp:LNAA when compared with a low ratio resulted in a significant increase of platelet-poor plasma serotonin in humans (33) and brain serotonin in rats (21). Although we did not measure serotonin directly, we did measure nocturnal urinary 6-SM, a byproduct of melatonin. 6-SM has been previously shown to be a valid measure of melatonin secreted under conditions of decreased serotonin function (14). The fact that serotonin acts as an intermediary product in pineal melatonin synthesis (34) means that melatonin metabolism directly reflects changes in serotonin function. A significant linear relation between plasma Trp and urinary 6-SM has been established (14). That study showed that after Trp depletion, the 6-SM concentration fell accordingly. In contrast, Trp supplementation led to a rise in 6-SM. In our study, the higher urinary 6-SM (per h) observed for the whole night collection than the evening collection is consistent with a peak melatonin secretion that occurs between 0200–0400, as would be expected of its metabolite. The highest concentration of 6-SM was observed after the high-GI meals (ingested 4 h and 1 h before bedtime), followed by the low-GI meal (ingested 4 h before bedtime). Although not statistically significant, these results were consistent with our hypothesis. It is likely that our study was underpowered for this outcome.
The timing of the high-GI meal also affected sleep onset in our study. The high-GI meal ingested 4 h before bedtime was more effective in shortening the SOL than was the same meal ingested 1 h before bedtime. The effectiveness of the timing of meals on SOL relates to the plasma appearance of Trp and LNAAs after ingestion of a high-carbohydrate or -protein meal. Previous studies have shown that Trp:LNAA peaked around 2–4 h after ingestion of a high-carbohydrate meal, and the ratio reached a trough around 4 h after ingestion of a high-protein meal (12, 33, 25, 35). Thus, these findings support our observations that a high-GI carbohydrate meal with low protein content, consumed at 4 h before bedtime, had a greater effect on shortening the SOL than that consumed at 1 h before bedtime. The fact that a high-GI meal eaten 1 h before bedtime can also have an effect on SOL is important, because different work and lifestyle demands often render meals being ingested late at night close to bedtime.
In the present study, the determinant dietary factor of GI was simply the type of rice being eaten. The fact that a simple manipulation of food intake can significantly improve sleep onset lends itself to a possible convenient, inexpensive, and noninvasive therapy for treating difficulty with sleep initiation. Future research that explores the potential benefit of manipulating the GI or GL of meals for persons with sleep disturbance is warranted.
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Acknowledgments
We thank Liz Barnes from the Human Research Committee of Sydney University for her helpful guideline of the statistical analysis. We also thank Pat Ruell, Biochemistry Lab, EXSS, Sydney University, for assisting with the urine melatonin analysis and Maria Fiatarone-Singh for reviewing the manuscript for us. We thank the volunteers who participated in this study.
AA, HOC, and CMC designed the study. AA and HOC planned the meal test. CMC, who was blinded to the treatments, scored all sleep studies. AA implemented the study protocol and did the statistical analysis of data. CMC and HOC oversaw the writing of the manuscript. No author had any financial interest in the organization supported this research. AA is a doctoral candidate at EXSS. HOC is a lecturer in Nutrition and CMC is a senior lecturer with a research focus on sleep at EXSS.
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Footnotes
↵2 Supported by Sydney University's PhD student research budget. The rice was provided by Riviana Food Pty Ltd, Victoria, Australia.
↵3 Reprints not available. Address correspondence to CM Chow, Delta Sleep Research Unit, School of Exercise and Sport Science, Faculty of Health Sciences, The University of Sydney, PO Box 170, Lidcombe NSW 1825 Australia. E-mail: [email protected]
Received June 8, 2006.
Accepted October 10, 2006.
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