A lot of times, before someone will get on board with a new dietary recommendation, you must disabuse them of commonly parroted “dogma” about weight loss. “You must eat multiple small meals a day to keep your metabolism moving” is one such misunderstanding.
This misunderstanding ties in with another myth: “negative calorie foods,” but that isn’t the topic of today’s discussion.
The complete and utter nonsense of needing to eat multiple small meals a day to “stoke the metabolic furnace” is a misunderstanding of the Thermic Effect of Food (TEF). This has been discussed here before, and it will again.
TEF, abbreviated, is that when we consume foods a percentage of that food is burned-as-fuel by the body for the sake of digestion. This percentage varies from macronutrient to macronutrient:
- Carbohydrates: 5 to 15% of the energy consumed
- Protein: 20 to 35%
- Fats: at most 5 to 15 %
So if, for example, you eat a piece of bread with a TEF of 8%, and that bread is 100 calories (for ease of example): your body will expend 8 calories to process that bread. Generally, for a normal diet with a mixed dietary composition, you can assume/expect an overall TEF of 10%.
Hopefully you can see where this is going: the misunderstanding was that “if my body expends calories to digest, then I should eat more often to burn more and ‘keep things moving.'” The problem with this logic is that whether or not you consume 1 big meal or 6 small ones, the TEF does not change.
- 6 x 300 calorie meals with an average TEF of 10% = 30 TEF-cals per meal x 6 = 180 TEF-cals burned total.
- 1 x 1800 calorie meal with an average TEF of 10% = 180 TEF-cals burned total.
As you can see, regardless of whether you get 30 “free” calories six times, or 180 “free” calories once: the amount your metabolism burns is the same.
Prevention of “starvation mode” is another argument people use justify the “eat multiple small meals” myth. Fact of the matter is: our metabolisms don’t work in the way that argument is expressed, or in the time frame often suggested by it; i.e. by skipping a meal. This will be addressed in a separate article.
At the end of the day: there is no magic or even defensible physiological reason to eat multiple small meals a day over however-the-hell-else you want to eat. Now, if eating multiple small meals helps you psychologically and enables you to adhere to a caloric deficit: go for it.
However, as with all things: I encourage my readers to keep the information in context. If someone tells you “you need to eat many small meals a day to keep your metabolism going,” then that person is wrong, and studies prove this. If, on the other hand, someone says: “You may find it easier to control your calories better if you partition your meals differently,” they could very well be correct.
As with most anecdotal evidence that isn’t supported by good science, though: advice such as the latter is subjective. The science of TEF is not.
If you’re interested in the studies I mentioned, the one regarding meal frequency can be found here, for full text you’ll likely need to subscribe:
“Studies using whole-body calorimetry and doubly-labelled water to assess total 24h energy expenditure find no difference between nibbling and gorging. Finally, with the exception of a single study, there is no evidence that weight loss on hypoenergetic regimens is altered by meal frequency. We conclude that any effects of meal pattern on the regulation of body weight are likely to be mediated through effects on the food intake side of the energy balance equation.”
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