More Meals=Higher Metabolism?
As a registered dietitian, it is my job to translate nutrition science into practical strategies for you to use in achieving your health and fitness goals. One of the most common misconceptions I come across in my practice is the belief that increasing the frequency of your meals will increase your metabolism and assist in your health and wellness goals. While achieving a consistent eating frequency can potentially assist you in a variety of ways (ex. appetite control, lean mass retention), boosting metabolism is not one of them according to the current scientific literature on the topic. Before we look at the studies investigating meal frequency and metabolism, we must first understand how this popular myth began.
It all started with TEF (Thermic Effect of Food)
The thermic effect of food (TEF) is the energy we use in order to digest the food that we consume. For the most part, the thermic effect of food accounts for about 10% of our daily calories. For instance, if your calorie needs are 2,000 calories that means that you burn about 200 calories just digesting the food that you eat. This led to the belief that if you increase the frequency of your meals, you increase the amount of calories you burn through TEF. Makes sense right? I hate to be the bearer of bad news, but that is not how that actually works.
Let me explain using some math. For example, lets say that you need 2,100 calories per day in order for you to achieve fat loss. Let’s compare the thermic effect of food for 3 meals a day and 7 meals per day. If you ate 3 meals a day, that would put you at roughly 700 calories per meal. If we take 10% of 700 calories, we would come to a TEF of 70 calories. Multiply that by 3 and you get a TEF of 210 calories for the day. Let’s compare that to 7 meals per day. If you ate 7 meals per day, each meal would be around 300 calories. 10% of 300 calories would equal a TEF of 30 calories per meal. Multiply that by 7 and you get a TEF of 210 calories, which is IDENTICAL to the TEF of 3 meals per day.
As you can see from the example above, TEF stays the same regardless of how many meals are eaten. Now let’s take a look at the available research on the topic.
What does the research say?
There are a multitude of studies examining meal frequency and metabolism currently available. For instance, a study done by Cameron et al. (1) investigated the impact of increased meal frequency and weight loss. Sixteen obese individuals (8 male, 8 female) were randomized into two groups. One group was assigned to 3 meals and 3 snacks per day while the other group was assigned to just 3 meals per day. Both groups had the same calorie deficit in place. At the end of the study, both groups lost about 4.7% of their body weight along with a 3.1 kg decrease in fat mass. There were no significant differences between groups when it came to adiposity indices or appetite. Other studies looking at meal frequency and weight loss have also found similar results between groups when calories are matched (3).
What can you do to boost your metabolism?
As you can see above, the claim that meal frequency positively affects your metabolism is not supported by the available scientific research. In fact, there is more research demonstrating that eating fewer meals has a more favorable outcome on weight loss as long as calories are matched (2). So does that mean that eating more than 3 times per day is bad? NO! Ultimately meal frequency should be subjective. What I mean by that is that you should find the meal frequency that allows you to stay the most full while maintaining appropriate calorie balance according to your goals.
So what can you do to boost your metabolism? The first thing is exercise with an emphasis on resistance training or high intensity interval training (HIIT). The second thing, which we can look back to TEF, is changing what you eat. For example, protein has the highest TEF of the three macronutrients with carbohydrates being second and fats being third. The easiest thing to do would be to increase your protein intake. With that being said, the impact is quite small so this is not a recommendation for you to just eat protein expecting to become shredded. You still need fats and carbohydrates for optimal health. The third thing would be to not even worry about trying to boost your metabolism. Instead focus on achieving consistency and adherence with your nutrition and exercise regiment.
How many meals should I eat then?
Lets recap. Does meal frequency affect metabolism? Based on the available research, the answer is no. Is it wrong to eat 6 meals a day? Nope. Is it wrong to eat 2 meals a day? Absolutely not (look at the success of intermittent fasting protocols). If meal frequency doesn’t effect metabolism, then does it even matter? Yes and no. If your goals are just general health and wellness (look good, feel good goals) meal frequency will have very little impact on your overall results. Ideally, you should aim to find a consistent eating frequency that allows you to stay full while maintaining caloric balance and aim for a diet based around whole foods. If your goals are more performance oriented, then meal frequency could provide numerous benefits to boost performance (ex. recovery).
Stay tuned for the next edition of Nutrition Myth Busting! For more information or a more personalized nutrition plan, feel free to contact us today!
- Cameron, J. D., Cyr, M., & Doucet, É. (2009). Increased meal frequency does not promote greater weight loss in subjects who were prescribed an 8-week equi-energetic energy-restricted diet. British Journal of Nutrition, 1. doi:10.1017/s0007114509992984
- Munsters, M. J., & Saris, W. H. (2012). Effects of Meal Frequency on Metabolic Profiles and Substrate Partitioning in Lean Healthy Males. PLoS ONE, 7(6). doi:10.1371/journal.pone.0038632
- Schoenfeld, B. J., Aragon, A. A., & Krieger, J. W. (2015). Effects of meal frequency on weight loss and body composition: a meta-analysis. Nutrition Reviews, 73(2), 69-82. doi:10.1093/nutrit/nuu017