“Don’t skip breakfast, it’ll make you fat.” “Go more than a few hours without food, and your body will go into starvation mode.” “Stick to six small meals a day.”
Though the reported findings may persuade people to eat their Wheaties, there's growing controversy about the significance of the results and the study's methods (or example, it turns out the breakfast skippers were also more likely to smoke, drink, and lead more sedentary lives.) It's clear that when we eat can impact how our body processes what we eat, and this study and its controversy are helping expand the conversation around that debate.
What's the Deal?
A recent study on a small group of Type 2 diabetics suggests two large meals per day can top six mini-meals for weight loss (of course, multiple media outlets have already framed the news as though it’s true for the general population). This may come as a surprise, since grazing on small, frequent meals seems like the widely accepted solution to staying slim. And amidst all the diet books and talk of “stoking the metabolic fire” (the idea that eating more snacks throughout the day helps speed metabolism), it’s easy to get wrapped up in the hype. The more we look to diet and fitness gurus (whatever their credentials may be), the easier it is to accept perfectly spaced feeding times and praised snacking as the route to a thousand-horsepower metabolism.
But it turns out the "frequent meal theory" was actually put to rest years ago, starting with a team of Canadian researchers. For eight weeks, a small sample of obese adults stuck to either three meals and three snacks a day or just three meals (both groups consumed the same amount of calories). The researchers found more meals did not equal greater weight loss Increased meal frequency does not promote greater weight loss in subjects who were prescribed an 8-week equi-energetic energy-restricted diet. Cameron, J.D., Cyr, M.J., Doucet, E. Behavioural and Metabolic Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada. British Journal of Nutrition, 2010 Apr;103(8):1098-101. . Since then, multiple other studies have backed up their conclusions Effects of increased meal frequency on fat oxidation and perceived hunger. Ohkawara, K., Cornier, M.A., Kohrt, W.M., et al. Center for Human Nutritioln, School of Medicine, University of Colorado Anschutz Medical Campus, Denver, Colorado. Obesity, 2013 Feb;21(2):336-43. .
Each time we eat — whether it’s a three-course steak dinner or four grapes — our metabolic rate increases slightly for a short period of time. It takes energy to get energy from the food we consume; this is called the thermic effect of food, or TEF (Check out this piece for a more detailed explanation.) Measuring the thermic effect of food. Reed, G.W., Hill, J.O. Clinical Nutrition Research Unit, Vanderbilt University, Nashville, TN. American Journal of Clinical Nutrition, 1996 Feb;63(2):164-9. . While we burn energy each time we eat the amount of energy is consistent with how many calories we eat, not when we eat them. We don't burn more energy just by eating more frequently. In other words, if I didn’t eat for most of the day day and then consumed all my food in two big meals, I’d have roughly the same thermic effect as I would if I split the very same amount of food over six meals Meal frequency and energy balance. Bellisle, F., McDevitt, R., Prentice, A.M. Hotel Dieu de Paris, France. British Journal of Nutrition, 1997 Apr;77. .
Eating lots of small meals isn’t a surefire way to make us slimmer, and regardless of the diet hype, researchers have known this for a while, too. So why does the theory persist?
One reason for the pervasiveness of meal frequency talk could be pro-snack research from a few decades back. But here's the problem: Many of these studies were performed under extreme parameters or in the very short term. For example, a 1989 study compared a three-meal diet and a 17-snack “nibbling diet,” which isn’t the most realistic way to eat long term Nibbling versus gorging: metabolic advantages of increased meal frequency. Jenkins, D.J., Wolever, T.M., Vuksan, V. Department of Nutritional Sciences, Faculty of Medicine, St. Michael’s Hospital, University of Toronto, ON, Canada. New England Journal of Medicine, 1989 Oct 5;321(14):929-34. Eating frequency and energy regulation in free-living adults consuming self-selected diets. McCrory, M.A., Howarth, N.C., Roberts, S.B., et al. Department of Foods and Nutrition, Department of Psychological Sciences, and the Ingestive Behavior Research Center, Purdue University, West Lafayette, IN. Journal of Nutrition, 2011 Jan;141(1):148-53. . Another reason the small meal theory persists is because frequent meals may help us better keep track of what we’ve consumed in a day. Splitting up calories throughout the day (versus just eating two larger meals) can be pretty labor intensive, require more awareness, and ultimately lead to weight loss because of behavior, not biology.
The bottom line: There’s no solid evidence that six small meals a day (or more) will automatically whittle our middles or make our metabolisms warm and toasty. Our bodies care more about how much we eat and what we eat, not when.
Do you feel you can control your weight best with six smaller meals? Or do you abide by fewer, larger meals? Let us know in the comment section below or tweet the author @nicmcdermott.