Even the most inactive among us burn calories simply to keep our bodies functioning normally — to stay alive. For example, your basal metabolism (the calories burned to keep your body functioning) makes up about 60% of the calories your body burns every day.
Non-exercise activity (daily activities, fidgeting, walking around the house) accounts for about 20% of total calories burned. Anywhere from zero to 10% of calories burned are the result of intentional activity (exercise). That leaves 10% of your total calories burned, called “the thermic effect of food” or TEF.
So, about 80% of the calories your body burns are pretty much out of your control. However, two of those calorie-burning factors — exercise and TEF — you can manipulate. We all know how to increase calorie burning with exercise. That leaves the 10% burned from TEF.
A recent review of TEF research suggests that a low TEF could be a contributing factor to obesity and that it may be possible to increase TEF.
- Physical activity: Aside from the calories burned from the activity itself, research suggests that active adults have significantly higher TEF (31% to 45%) compared with sedentary adults. It was found to be true of both younger and older adults.
- Meal composition: Studies show that a high-carbohydrate meal triggers a higher TEF than a high-fat meal and the type of fat may also make a difference. Polyunsaturated fats, such as those found in corn and soybean oils, have a greater TEF than monounsaturated fats or saturated fats.
- Processed vs. unprocessed foods: Meals containing unprocessed grains may have a significantly higher TEF compared with unrefined grains. For example, eating a sandwich made with whole grains vs. a sandwich made with bread from refined flour has a higher TEF. According to Hana Kahleova, M.D., Ph.D., M.B.A., director of clinical research with the Physicians Committee for Responsible Medicine in Washington, D.C., and one of the authors of the review, “A plant-based diet increases the TEF by about 16%.”
- Meal frequency: Several studies have found that having a single large meal resulted in at least a 30% increase in TEF compared to eating three or four smaller meals. TEF can be 2.5 times higher with the morning meal, compared with dinner, and be higher in the afternoon, compared with eating at night. Kahleova points to the saying “eat breakfast like a king, lunch like a prince, and dinner as a pauper,” and says this concept has research to support it and is likely to offer the most calorie-burning benefits. Eating slower, instead of rushing through a meal, may also increase TEF.
Kahleova says “More research is needed to estimate how much we can increase the TEF by combining all these approaches,” adding that individually they have solid evidence behind them and can be recommended as a way to boost TEF and possibly aid in weight management.
(Environmental Nutrition is the award-winning independent newsletter written by nutrition experts dedicated to providing readers up-to-date, accurate information about health and nutrition in clear, concise English. For more information, visit www.environmentalnutrition.com.)
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