October 28, 2011
“Eat every 1.5-3 hours.”
“Be sure to snack frequently to keep your metabolism elevated.”
“Don't skip meals or your body will go into starvation mode.”
I’m quite guilty of preaching messages like this as if they were the gospel of fitness and nutrition. As early as two years ago, I was telling clients and writing in magazines to “eat small, frequent meals so you keep your metabolism elevated” or to “graze like a squirrel so that you burn more calories”.
But eventually, I realized this wasn’t true.
It started when another, more informed nutritionist asked me to drag out the research studies that proved that eating more than three meals per day would elevate the metabolism.
So for two weeks, I combed research journals, the National Institutes of Health, library books, and every resource I could get my hands on.
And guess what?
I could find zero evidence that eating any more than three meals per day does any good at “boosting your metabolism”, “burning fat” or “losing weight”.
Basically, as long as your total caloric and nutrient intake stays the same, then your metabolism, at the end of the day, stays the same as well. One study that carefully demonstrated this, published in The British Journal of Nutrition, randomly assigned overweight men and women to very strict low-calorie diets and followed the participants for eight weeks.
Each subject consumed the same number of calories per day, but one group ate three meals a day and the other ate six meals a day. Both groups lost significant and equivalent amounts of weight, with no difference between the groups in fat loss, appetite control or hormones that signal hunger and appetite. Other studies have had similar results.
Especially compared to the reliable metabolic boost of exercise, frequent snacking or “grazing” doesn’t do much at all for you.
As a matter of fact, when you restrict feeding times to three meals per day your body produces more anti-aging and muscle building hormones. When you eat more than three times per day, you produce more fat-building and age-accelerating hormones. By keeping your blood sugar levels constantly elevated with snacking, you never really allow your body to learn how to reliably burn fat as a fuel.
So where did this “snack frequently” myth come from?
There are two basic reasons this myth has been perpetuated.
The first goes is the annoying false message of “starvation mode.” The idea behind this is that when not much food is around, the body burns fewer calories in order to conserve energy, just in case the food shortage continues. In ancient times, during a famine, you’d need to live on your stored fat, and down-regulating your metabolism seems like a pretty good way to do this.
This seems to makes sense, but it’s only partially true. Your body does respond to a long period of very low calorie intake by slowing your metabolism to conserve energy – but it takes about three days of complete fasting or very low calorie restriction for your body to do something as drastic as down-regulating your metabolism.
Last time I checked, we didn’t have a serious problem with people who don’t snack going on 3 day fasts or eating 500 calories a day.
The second way this myth probably got perpetuated is because of something called the thermic effect of food, which basically refers to the fact that when you digest food, your body has to burn some calories in order to do that.
So if you eat a meal that contains 300 calories, your body might burn up to 30 calories digesting and absorbing that meal.
And this has led some people, including many famous personal trainers and nutritionists, to assume that if your body is constantly digesting food, then it will constantly be burning calories. So if you go too long between meals, you shut down that “calorie burning fire that you’re supposed to be stoking”.
The truth is this: at the end of the day, the thermic effect of food is identical – whether you ate three times, five times, or ten times. This is because the thermic effect of food is based on the total quantity of food, and not on the frequency of food intake.
Ultimately, if you’re eating fewer than three times a day, research has suggested that you may end up eating a less healthy diet or gaining weight. But this is probably because you’re ravenous by the time you get to dinner after having fasted for 10 hours since breakfast (and vice versa) and not because anything magical happens to your metabolism when you snack all day.
I personally do it like this:
-breakfast between 7 and 9
-lunch between 1 and 2
-an afternoon snack before my workout
-dinner between 6 and 8
And that’s it. Compared to my old strategy of trying to eat 6-10 times per day, this is way easier. Interestingly, it’s also much easier to maintain weight, and I more completely digest my meals.
Grazing is for cows. So free up some time, quit trying to “snack every 1.5-3 hours”, and just eat when you’re hungry. If you have feedback, questions or other comments, simply leave them below!