The Thermic Effect of Food

Thermic effect of food (TEF) is a component of basic metabolism just like resting metabolic rate and exercise and the TEF of food uses up about 10% of the caloric intake of a given time period. But what exactly is this TEF and what foods raise it, so you can burn more calories? Well, as you probably guessed, fat is very easy to process and has a very low TEF, while protein is harder to process and has a much larger thermic effect; a protein rich meal boosts your metabolism by 30% and a high carbohydrate meal only boosts it by 4% (because protein has to be broken down into amino acids which is a labor-intensive process in cells), which is one of the reasons why higher protein intake may be helping folks with weight loss.

For example, if you were to consume 300 calories in pure protein such as by a protein powder, or egg whites, the TEF would burn off 81 of those calories just during the act of digestion, leaving you with 219 calories. Pretty cool, huh? The thermic effect of food is of course increased by both aerobic training and by anaerobic weight training but the increase is marginal, amounting to 7-8 cal per hour and the primary determinants of daily TEF are the quantity and composition of the food ingested. You may have heard that raw celery and grapefruit are often claimed to have negative caloric balance (requiring more energy to digest than usable energy received from the food), presumably because the thermic effect is greater than the caloric content; this is due to the high fiber matrix that has to be unraveled to access the carbohydrates.

In addition, researchers in Australia determined that a group eating salmon and tuna lost 22% more weight than a focus group eating the same number of calories but no salmon or tuna. And you’ve probably heard that celery burns more calories than it provides. Hot peppers, ice water, green tea, and coffee are also great for upping the TEF, as are spices like cayenne pepper, cinnamon, celery seed, fennel seed, garlic, ginger, mustards & chili sauce, parsley and salsa.