Where This Myth Stems From
“Hey bro, you gotta eat every 2 to 3 hours to boost your metabolism.”
Does that sound familiar?
This is typically the reason why most folk feel the need to segment their daily calorie allowance into such small servings and eat every few hours.
It’s often the false notion of thinking of your metabolism like a fire – that by dumping a load of fuel on the fire in one go (the fuel in this case being calories, and the fire being your metabolism) you get a big spike, and then it dies down to nothing, whereas smaller doses of fuel/ calories keeps the fire burning constantly.
This made people think that by eating smaller meals spaced just a few hours apart, they’d increase metabolic rate, and as such, increase daily calorie burn, and ultimately, lose more fat.
Makes sense, right?
But then remember – your body is NOT a fire, and this metaphor is, quite frankly, pretty flawed.
What the Science Says
Let’s look at the numbers.
The idea of a “metabolism boost” is known as TEF, or the Thermic Effect of Feeding.
This is the calorie burn created by eating a meal.
Typically, protein calories cause a 20-30% increase in TEF while carbs elicit a 6-8% increase and fats just 2-3%.
Therefore, if we say an average mixed meal has a 15% TEF (so if your meal contained 400 calories, you’d burn off 60 through digestion) that means that if you ate 2500 calories per day; you’d burn 375 through TEF.
1 meal per day of 2,500 calories = 375 TEF calorie burn.
4 meals of 625 calories = 93.75 calorie burn per meal. Multiplied by 4 meals = 375 calorie burn.
10 meals of 250 calories = 37.5 calorie burn per meal. Multiplied by 10 meals = 375 calorie burn.
As you can see, all meal frequencies result in exactly the same calorie burn over the course of 24 hours.
Additionally, a study from the “American Journal of Clinical Nutrition” concluded that –
“When meal frequency is decreased without a reduction in overall calorie intake, modest changes occur in body composition, some cardiovascular disease risk factors, and hematologic variables.” (1)
Showing that potentially, even a lower meal frequency may be better.
We also have this from the “Journal of the International Society of Sports Nutrition” –
“Like many areas of nutritional science, there is no universal consensus regarding the effects of meal frequency on body composition, body weight, markers of health, markers of metabolism, nitrogen retention, or satiety.”
“Increasing meal frequency does not appear to favorably change body composition in sedentary populations.” (2)
“But Doesn’t Metabolism Drop from Not Eating?”
In a word – no.
Your metabolic rate remains stable when you’re not eating, and actually, may even increase for up to 72 hours into a fast.
Anecdotally too, many people mention an increased satiety when spacing meals further apart, rather than constantly eating.
This is likely to do with the fact that by eating fewer meals over the course of a day, each one can be slightly bigger and more calorie-dense, and therefore much more filling.
It also gives you chance to eat more of your favourite foods in slightly bigger quantities, while still ensuring that you get plenty of protein, fibre and micronutrients every time you eat.
Living Your Life
Dropping your meal frequency and ignoring the bro advice of having to eat every few hours certainly makes life easier too.
It’s a real pain having to carry round boxes of Tupperware with you when you’re out and about, or having to make an excuse every 2 hours to go to the bathroom, or stopping in the middle of an important task at work just so you can “stoke your metabolism.”
Sure, some guys can stick to this okay, but going from 6, 7 or 8 meals per day down to, say, 3 or 4 definitely makes life a whole lot easier.
Above all, you should do what works best for you in terms of convenience.
That might be eating something small every couple of hours – there’s nothing wrong with that.
Just know that you don’t HAVE to do this.
I’ve found that most clients respond best to 3 to 5 meals per day, as each one is big enough to be filling, but you don’t go too long between meals and get hungry. (Or worse … HANGRY!)
Extreme meal frequencies are probably best avoided by most folk – meaning that just 1 meal per day might be going a little too far, as you won’t be getting frequent protein doses, and 10 meals per day just isn’t practical.
Aside from that though, do whatever fits your lifestyle, just make sure you hit your daily calorie and macro goals, and you’re good to go.