May 2011 15
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Carbs at Night Do Not Make You Fat

A commonly held belief in the fat loss arena is you should not eat carbohydrates after 5-6 pm because, by some magical, mystical, transmutative process, they suddenly become more fattening after this time than in the morning. Yeah, right – and I have a buddy who looks like a musclebound version of Brad Pitt during the day, but morphs into a Dick Cheney look-a-like the minute the clock strikes six. You wouldn’t believe the havoc it wreaks on his sex life, poor bugger.

If the evening carbs theory sounds like nonsense, that’s because it is. However, this myth is amazingly pervasive in the diet industry; so pervasive, in fact, that I devote an entire chapter to it in The Fat Loss Bible.

Legend has it that after 6pm, this innocent-looking plate of linguine turns into a heinous, fat-producing monster that will leave you fatter than a sumo. At midnight, it turns into a pumpkin.

The latest study to debunk the don’t eat-carbs-at-night dogma comes from Israel. Seventy-eight obese members of the Israeli Police Force took part in a 6-month randomized clinical trial. The experimental group was prescribed a low-calorie diet (20% protein, 30–35% fat, 45–50% carbohydrates, 1,300–1,500 kcal) providing carbohydrates mostly at dinner. The control group consumed a similar diet, except that carbohydrate intake was spread throughout the day.

So what happened after six months? Did the group eating most of their carbohydrates at night lose less weight, as prevailing dogma would predict? Nope – they actually lost slightly more weight (-11.6 versus -9.06 kg) and body fat (-6.98 versus -5.13%) and experienced greater reductions in waist circumference (-11.7 versus -9.39 cm). Only the reduction in weight reached statistical significance, however[1].

Before some huckster rushes off to write a hyperbolic book about the “Nighttime Metabolic Advantage!”, there is a far more straightforward reason for these differences. Overall, the experimental group experienced much less hunger and less diet-derailing pre-occupations with food than the control group.

For many people, eating large amounts of carbohydrate during the day can lead to erratic blood sugar fluctuations that can increase hunger and food cravings. For these folks, following the “avoid-carbs-at-night” tenet is likely to obstruct rather than help their weight loss efforts.

Eating carbs after 6pm won't hurt you. Consuming alcohol after 6pm is an entirely different story.

Diets Don’t Work. Or Do They?

Speaking of oft-repeated fat loss mantras, everyone’s heard the old “diet’s don’t work” and “dieting makes you fat” lines. According to the purveyors of these clichés, you should never cut calories in order to reduce your bodyweight, because you’ll only end up fatter than ever. Instead, you should follow said purveyor’s unique fat loss method, which of course usually proves far more useless than sensible caloric restriction could ever dream of being.

Let’s get something clear right now: It is physically impossible to lose weight (save for water and fecal losses) if you don’t consume less calories than what you expend. On the odd occasion that the methods of the anti-diet crowd do in fact work, it’s only because they inadvertently result in a calorie deficit.

There are a few ways in which you can create a calorie deficit:

1)      Reduce your calorie intake;

2)      Increase your energy expenditure via physical activity;

3)      A combination of 1 and 2;

4)      Load up on potent thermogenic drugs.

Option number 4 might sound great to those who prefer the “easy” route, but entails side effects that range from nervous jitters to death (in the case of overzealous DNP use). While death is unarguably the most effective fat loss strategy in existence – you will eventually get down to a super-shredded 0% - it has its obvious downsides. Even non-fatal effects such as excessive central nervous system stimulation, blood pressure elevations, heart racing and arrhythmias render this option a poor choice for many folks. Due to the risk of adverse effects, I personally do not endorse option 4.

Some people’s genetic make-up may favour rebound fat gain after extended periods of caloric restriction, in what was once a protective response against temporary food shortages. Your ancestors of 100,000 years ago often had to endure periods of food scarcity, so the ability to overcompensate by stockpiling excess calories in the form of body fat was actually a survival advantage. Unfortunately, your habit of stockpiling excess calories from biscuits and ice cream after an exhausting session of TV watching does not confer the same advantage.

No, really.

In a letter to the British Journal of Nutrition[2], Geoffrey Cannon points out that this once favourable adaptation becomes maladaptive, only in conditions when, after the period of energy restriction, people have free access to food and drink ad libitum, in particular when the food and drink is energy-dense, and most of all when the subjects are sedentary and therefore can be described as being in unnaturally low energy balance. It is only recently in human history that these three conditions have often been met, and these are now typical human circumstances in most countries in the world.

Dieting doesn't work - if you don't stick to your diet.

In another BNJ paper[3], Lowe and Timko point out that dieting has developed a negative reputation among many commentators, but the wisdom of dieting depends on what kind of dieting is involved, who is doing it, and why. Thus, depending on what one means by the term, dieting can be quite harmful, merely ineffective or actually beneficial. They argue that judgements about the desirability of dieting should consider the likely consequences to particular individuals of engaging in, or not engaging in, dieting behaviour. As the authors explain, “Dieting to lose weight is far more appropriate for an overweight, middle-aged man with risk factors for heart disease than it is for a normal-weight female teenager who is not susceptible to weight gain, but nonetheless feels like she is too fat.”

An example of harmful “dieting” would be the pathology of bulimia nervosa, which is characterized by alternating periods of caloric restriction and binge eating. Fortunately, such extreme outcomes do not apply to most folks dieting for weight loss.

Most people who attempt weight loss will regain the weight over the longer term. This is not because caloric restriction does not work – it does, as has repeatedly been demonstrated in clinical research. But even in people who achieve short term weight loss success, most of the lost weight is regained over the longer term due to a failure to maintain the required caloric intake. This phenomenon is consistent with the conclusion that in the long-term dieting in overweight individuals is neither beneficial nor harmful, but rather simply ineffective. A similar conclusion has been reached when the psychological effects of diet-induced weight loss in overweight individuals has been studied. The beneficial effects of weight loss on self-esteem, body image, binge eating, etc. gradually erode when lost weight is regained. That is, after regaining weight, overweight individuals are neither better off nor worse off psychologically; they essentially return psychologically toward their pre-treatment status.

Unfortunately, we live in a world where constant and abundant availability of energy-dense foods provides an ever-present obstacle to those seeking to lose weight. There’s no getting around it: if you’re serious about losing weight, then discipline, determination and pre-planning strategies to avoid dealing with potential weight loss roadblocks are essential. Getting involved in a sport or physical activity that you enjoy, one that requires high energy expenditure, is also an excellent way to promote sustainable fat loss. If you enjoy an activity such as cycling, running, rollerblading, martial arts primarily for its intrinsic characteristics then it’s much easier to maintain motivation, as you will be less likely to view it as a chore that must be endured in order to achieve fat loss. If you’re interested, I discuss numerous effective strategies for smashing through fat loss obstacles in The Fat Loss Bible.

Anthony Colpo is an independent researcher, physical conditioning specialist, and author of the groundbreaking books The Fat Loss Bible and The Great Cholesterol Con. For more information, visit or


  1. Sofer S, et al. Greater weight loss and hormonal changes after 6 months diet with carbohydrates eaten mostly at dinner. Obesity, 2011 Apr 7. [Epub ahead of print].
  2. Cannon G. Dieting. Makes you fat? British Journal of Nutrition, 2005; 93: 569–570.
  3. Lowe MR, Timko CA. Dieting: really harmful, merely ineffective or actually helpful? British Journal of Nutrition, 2004; 92 (Suppl. 1): S19–S22.


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