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Save Your Carbs For Dinner?


Diurnal changes in hormones and metabolism are well known and how these can be influenced by timing and sequencing of external stimuli (e.g. eating, exercise, sleep, etc.) has always been of considerable interest.

A study by Sigal Sofer and colleagues from the Hebrew University of Jerusalem, Israel, published in OBESITY, suggests that eating most of your carbs at dinner may have beneficial effects on hormonal patterns, metabolism, and lead to more weight loss than eating a similarly calorie-restricted diet with carbs spread out throughout the day.

The rationale for the study as stated by the researchers is that:

“…consumption of carbohydrates mostly in the evening would modify the typical diurnal pattern of leptin secretion as observed in Muslim populations during Ramadan. The experimental diet induced a single daily insulin secretion in the evening, thus it was predicted that the diet would lead to higher relative concentrations of leptin starting 6–8 h later i.e., in the morning and throughout the day. This may lead to enhanced satiety during daylight hours and improve dietary adherence.”

In addition,

“Studies have shown that there is a negative correlation between insulin and adiponectin levels. Since the experimental diet used in this study reduces insulin secretion during the day, it was also hypothesized that adiponectin concentrations would increase throughout the day improving insulin resistance, diminishing symptoms of the metabolic syndrome and lowering inflammatory markers.”

A total of 78 male subjects (policemen) with a BMI greater than 30 were randomized to 6 months of 1,300–1,500 kcal/day diets, with either the carbs served mostly at dinner (test) or throughout the day (control).

Subjects eating their carbs in the evenings lost more weight (11.6 vs. 9.06 kg) and had lower hunger scores as well as greater improvements in fasting glucose, average daily insulin concentrations, and insulin-resistance.

There were also greater improvements in lipid profiles, CRP, and other relevant markers in the intervention group.

While leptin levels dropped in both groups (not surprising given the weight loss), the leptin decrease was less in the late-carb-eaters than in the control group, and adiponectin levels increased significantly only in the intervention group. The authors suggest that these hormonal changes may perhaps explain the improved metabolic control and lower hunger scores in this group.

However, the authors are also careful to point out that:

“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.”

They certainly have my attention.

AMS
Edmonton, Alberta

p.s. Registration for the International School on Obesity Research and Management (ISORAM 2012, Lake Louise March 25-30 is now open – click here to register).

Sofer S, Eliraz A, Kaplan S, Voet H, Fink G, Kima T, & Madar Z (2011). Greater weight loss and hormonal changes after 6 months diet with carbohydrates eaten mostly at dinner. Obesity (Silver Spring, Md.), 19 (10), 2006-14 PMID: 21475137

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10 Comments

  1. Um. 6 months of a 1,300–1,500 kcal/day diet sounds like absolute hell and completely unsustainable, especially for physically active men (Police? The last thing society needs is irritable police who are obsessing over food and can’t concentrate).

    So, really who cares how much weight they lost and how hungry they were. They almost certainly won’t be able to keep those eating habits up indefinitely, and they’d probably adversely affect job performance. Even Ancel Keyes’ semi-starvation study subjects got to eat hundreds of calories a day more than that, and look at the psychological shape they were in.

    Also, comparing this to Ramadan is odd to say the least, since the eating after dark during Ramadan isn’t calorie restricted, and the daytime fast even excludes liquids. I don’t see how that would have a truly similar physiological effect to what’s described above.

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  2. The proof of the pudding is in the eating…

    I’d like to know how much these men weighed six months after their six-month quasi-starvation diet.

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  3. What’s the rationale for going through this merry-go-round with leptin and adiponectin when biology textbooks throughout the world teach that insulin directly regulates fat accumulation at the adipocyte?

    I have a pretty good idea of the rationale. Leptin is the satiety hormone. It rises to suppress hunger during the meal and that’s why we stop eating. This idea obeys the Ein-Eout hypothesis of obesity which says that obesity is a disorder of overeating. Our paradigm remains intact. There are several problems with this. The Ein-Eout hypothesis explicitly ignores hormones because it is based not on biology, but on the Laws of Thermodynamics. The hypothesis relies exclusively on calories and here we have a study that doesn’t look exclusively at calories, but at carbohydrates and its effect on hormones including insulin. Leptin is associated with obesity: The higher it is, the more obese we are. And injecting leptin has no effect on obesity, unless there’s a leptin deficiency like with insulin and type 1 diabetes. It’s difficult to reconcile the Ramadan conclusion with this data about leptin.

    The study tries to say this: It’s not about calories (carbs), therefore it’s all about calories (leptin;satiety;calories eaten).

    If I was the one signing the checks for a new study for “more research to understand the mechanisms…”, I wouldn’t.

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  4. Well, on my N=1 experiment — by accident, for years — I can only say two things:

    1. My experience supports this.
    2. It is not a good thing.

    Yes. I managed to develop a once a day, in the evening, eating habit for lasted me about 15 years. I was simply not hungry until then. I only ate then. This resulted in under-calorie-ing.

    Most of the time. The side-effect of under-calorie-ing and under-nutrient-ing especially — I mean in the real world I live in — is eventually the body (moreso the more “under” they’ve been) will freak-out and lead to the “see-food” diet. I suspect this is not commonly realized in science because in research, this would merely be seen as either (a) after the trial, or (b) a self-reporting error, or (c) if reported, simply a failure to maintain the rules. Whether anybody’s recognized that depriving someone’s body–especially someone already fat who probably has longterm malnutrition that got them that way–only works for so long before the rubber-band effect kicks in.

    What I managed to do while ‘successfully’ staying under-calorie ‘most’ of the time, and ‘not hungry’ until night, was gain enormous amounts of weight, while of course trashing my metabolism to the point it can maintain extreme weight on what would seem impossibly small calories, if people like Dr. Friedman hadn’t publicly confirmed the same thing happens in metabolic ward studies. (If I say it, I’m probably lying about food intake because I’m fat. If he says it, it’s ok.)

    Killing people’s appetite to get them to eat less, whether this is done via chemical straightjacket of ‘managing leptin’ or physical straightjacket of gastric bypass, is not the answer to anything. Malnutrition is the heart of the overal medical trainwreck in our culture, and finding a way for people to undereat does not improve anything.

    PJ

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  5. I should add to my previous comment: getting people off the foods that spawn overeating of damaging foods (e.g. grains) is of course important. But getting people to ‘stop overeating bad things’ vs. getting them to ‘successfully undereat whatever good things they eat’ are not the same thing at all. – PJ

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  6. I’m most interested in the potential for increased adiponectin concentrations and corresponding reduction in inflammatory markers. Several members of my family have arthritis, including one male who is very slender and needs to eat at least 3500 calories a day on average (or he feels terrible and loses weight.) I wonder if shifting a greater percentage of his carb intake to evening (without reducing his overall calorie intake) could help to reduce his inflammation (and, hence, reduce his pain).

    In fact, I wonder if the noted improvements in the intervention group (those who concentrated more of their carb intake in the evenings) would have resulted anyway–even with a higher calorie diet. That is, perhaps some of the improvements in their fasting glucose, insulin concentrations and insulin resistance resulted from the alteration in the timing of their carb consumption–independent from their reduced calorie intake.

    In my personal experience, the worst symptoms of metabolic syndrome were chronic fatigue, chronic muscle weakness, fibromyalgia, and chronic hunger. When alterations in carb consumption can reduce such symptoms (in SOME people), then increased mobility and activity levels–and greatly improved well-being–may result. In my case, weight loss also resulted. However, significant symptom relief began BEFORE any noticeable loss of weight.

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  7. Thanks for reporting this study Dr. Sharma. It raises several questions for further study! I read the article and didn’t see a control for shift work. It also didn’t seem serum cortisol levels were measured throughout the day. Police are not immune to stress and the nature of their work can be very stressful. Possibly you should cross-reference this article with your May 28, 2011 post on Stress.

    It would have been helpful to see exact gram amounts of carbohydrates as balanced with protein and fat as opposed to a listing of foods eaten. The study reminds me of the work done by the Keller’s on Carbohydrate Addiction – theirs was an “all you can eat within 1 hour at supper” diet, with minimal carbohydrates at any other time of the day.

    It would be interesting to see a similar study done with the troops arriving home from the war torn countries.

    If there is a connection with stress and this type of diet, then perhaps those who were previously unable to lose weight, who now find this type of diet works for them, may realize they were unknowingly under considerable stress. CBT methods could then further assist in helping to identify and manage stress in these individuals. Also, this raises the question of how stress interferes with adiponectin concentrations. What is the cost per patient of measuring adiponectin concentration? Would there be any positive benefit in informing a patient of his or her own personal levels and changes in these levels of adiponectin concentrations during the day and over several months?

    Finally, this study showed that weight loss and health improvements occurred obviously with ongoing support and consequent mindful awareness of the officers over a period of 6 months. I bet none of them were at stage 3 or 4 in the “staging system” – yet they received profound benefit from such focused attention, likely exponentially reducing further cost to their health care system. If they were educated about the study, they learned more than one would through the weight wise program. I agree it would be interesting to do a longitudinal follow-up with them.

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  8. Why stop at just low carbohydrate through the day? We humans need very few carbohydrates, adequate protein, and a bit of Omega 3 fats. The remainder of required energy can be made up of carbohydrates or fats. We are going to get enough O6 regardless of what we eat. Lots of vegetables to provide minerals and vitamins, and fat works. Without large insulin production, hunger is not as much of an issue.

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  9. Sounds like a bit of cherry picking. I think the men lost weight because of the overall lowered calories (13-1500 for MEN!?), not because of the night carbs. It’s hard to say for sure because there are other factors involved, like the composition of the meals, types of carbs (starchy vs non starchy), individual metabolism, etc.

    What happened when they upped their caloric intake afterward?

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  10. I agree with Lisa, a low calorie diet will definitely cut down the weight, regardless of the kind of calories or time of the day. In my opinion this is mathematics.

    However, eating food in a sequence to lower hunger is of upmost importance for overweight people of ex-dieters on maintenance.

    It’s very simple, less hunger results in less eating and less weight.

    Therefore, does anyone knows the amount of fibers, proteins, carbs, fat & type of fat consumed at each meal during this experiment ????

    During the past two years, I have lost 47% of my body weight with a low level of exercises. I made countless experiments to find the food to eat now in order to prevent hunger in one, two, three or four hours.

    I have the very bad, 30 year old habit to go out for dinner twice a week. I take a light and healthy meal before leaving the house, therefore, these dinners are only a mode of entertainment with wine and empty calories food. (I however decided to starve myself by drastically cutting down on wine and tasty foods during these dinners)

    However, for the past month I am running the experiment of (before entering the restaurant) reading myself the riot act to warn myself to drink only one glass of wine and not eat.

    In the restaurant I pay a heafty tip to pay for the use of a chair, I place a paper in front of me, on which it is written: TAKE ONE GLASS OF WINE, DO NOT TOUCH THE BREAD.

    While the others place their orders, I go outside and eat this 2-3. ounces solution: Blended mix of 6 legumes unsalted, one table spoon of grinded flax seeds, spiced to taste.

    Eating this solution of about 150 calories makes me skip a 1,500 calories meal without craving.

    I made the experiment of drying this solution with a food dehydrator. Eating the solution in a cookie form has very little effect versus the semi liquid form.

    My leptin receptors are defenitely broken down, (I even doubt I have any) as I have never left a particle of food in my plate, (even during the past two years) while my wife, which has no weight problem, has never eaten all her plate. Furthermore, if she offers me the rest of her plate, most of the time I do eat it, if I decline, I feel a craving at what seems to be the bottom of my stomac.

    For the past two years, humus and tofu spread have replaced butter and other need of a spread. I could not eat only a 30 grams portion, regardless how hard I tried. Therefore, upon returning from the grocery store, I subdivide the humus and tofu spread containers in multiple 30 grams bags which I freeze and thereafter eat in 30 grams portion. My purchase of these foods has come down by 90%.

    As you can figure out, I never or rarely use my leptin receptors, I must take psychological or physical steps to cut down my food intake.

    I keep on seaching for ways to cut down hunger.

    By the way, I eat a computorized balanced diet. As my brain can not regulate my food intake, I let the computor do it for me.

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