How many times have you heard the advice to eat more often (i.e. three meals, and two or three snacks per day) because you will supposedly burn more of the calories you eat because eating more often boosts your metabolism?
If you think the claim sounds a little fishy, your instincts are good—the claim that eating more often boosts your metabolism is completely false.
Here’s all you need to know. A small part of your total energy expenditure is called the thermic effect of food (TEF). TEF simply represents the amount of energy (calories) your body uses to digest your meal. On average TEF amounts to just 10% of the calories in your meal.
At the end of the day your TEF remains an average of 10% regardless of whether you divide your calories into 3 meals, 6 meals, 10 meals, or however many! The only way to increase TEF is to eat MORE calories, and the only people who need to eat more calories are ones who are trying to GAIN WEIGHT!
Furthermore, eating more frequently also has NO effect on your underlying metabolic rate.
Here's something to think about too. The average adult BMI (for both males and females) today is 24-pounds higher than it was in 1960. Was anybody recommending snacking between meals back in 1960 and earlier when average adult BMIs were in the healthy range? No, the pattern was pretty much three-meals-a-day, and snacking was viewed as something that would "ruin your appetite" for the next meal.
If you like to eat smaller meals at breakfast and lunch, then you do have unused calories to allot to mid-morning and mid-afternoon snacks, and that's fine, but there's no magic from the pattern.
Look, you should honor your hunger by eating when you're hungry. And conversely, honor your lack of hunger by abstaining from snacking if you are not physiologically hungry. The desire to eat what crosses your path is a Pavlovian response (not true hunger). [See my blogs on stimulus control for ideas how to deal with that challenge.]
Metabolic rate and TEF aside, are there any benefits to eating more frequently? Yes.
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If you are trying to gain weight, you may be able to put on more lean body mass (muscle) if your protein intake is more evenly distributed between meals and snacks throughout the day.
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Increased meal frequency also seems to lead to lower LDL, total cholesterol, and insulin secretion.
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Shifting from a night-eating pattern (people who only eat in the evening) to a breakfast, lunch and dinner pattern appears to decrease hunger, as well as improve cholesterol readings and insulin (as above).
The Bottom Line: While there are some potential benefits to dividing your calories into more than three meals per day, an increase in your metabolic rate isn’t one of them. Additionally, the size of a meal is an important factor in satiety. So, not everyone has a big enough calorie budget--especially if you are already on a reduced calorie level for weight loss--to pull calories away from their main meals without also reducing the satiety from those meals, which would obviously be counter productive.
Actionable advise: You do have control over two major factors in the energy balance equation: how much (and what) you eat, and how much you move. Forget about all the half-baked notions to otherwise rev-up your metabolism. Instead focus your energy on the things you do have control over!
Best,
-Dorene
For more on this topic also see:
Breakfast Boosts Metabolism -- Fact or Fiction?
What do you really know about your metabolism?
How to Lose Weight 101: Understanding Energy Balance
References:
1. Mattson, MP. The need for controlled studies of the effects of meal frequency on health. Lancet 2005;365(9475):1978-1980.
2. La Bounty et al. International Society of Sports Nutrition position stand: meal frequency. Journal of the International Society of Sports Nutrition 2011;8:4.
3. Cameron JD. et al. Increased meal frequency does not promote greater weight loss in subjects who were prescribed an 8-week equi-energetic energy-restricted diet. Fr. J. Nutr. 2009;Nov.30:1-4.
4. Verboeket-Van De Venne, et al. Effect of the pattern of food intake on human energy metabolism. Br J Nutr 1993;70:103-115.
5. Taylor MA, Garrow JS. Compared with nibbling, neither gorging nor a morning fast affect short-term energy balance in obese patients in a chamber calorimeter. Int’l J Obes 2001;25:519-528.
6. Bellisle F, et al. Meal frequency and energy balance. Br J Nutr 1997;77(Suppl.1):S57-S70.