Also known as the thermic effect of food, dietary thermogenesis, or diet-induced thermogenesis, DIT, is the process of energy production in the body caused directly by the metabolizing of food consumed. Dietary thermogenesis is influenced by factors relating to the composition of the food and the physical state of the individual. A 2004 analysis published in "Nutrition and Metabolism" of research on dietary thermogenesis found that in an energy-balanced state, a mixed diet of proteins, fats and carbohydrates produced an energy expenditure from dietary thermogenesis that constituted 5 to 15 percent of total daily energy expenditure.
Factors relating to the food you eat could influence their associated rate of dietary thermogenesis, in particular their energy content, or calories, and macronutrient composition. A 2008 study reported in "Metabolism" found that eating protein produces greater dietary thermogenesis than eating fat. The dietary thermogenesis of carbohydrates falls somewhere between the two. The 2008 study further suggested that a low rate of dietary thermogenesis following frequent or recurring fat consumption could be a factor in obesity.
Thermogenesis plays an important role in regulating body weight. Your weight is dependent on the relationship between two key factors: food taken in and energy put out. Thermogenesis is one of the three main components, along with basal metabolic rate and physical activity, involved in the energy side of that equation. Specifically, thermogenesis accounts for all energy expended in the resting state above and beyond your basal metabolic rate. As such, a high dietary thermogenesis may help promote weight loss while a low dietary thermogenesis may help promote weight gain.
According to the 2004 "Nutrition and Metabolism" study, protein is one of the primary factors in determining dietary thermogenesis. It is also the most significant influencing macronutrient in determining dietary satiety, or a feeling of fullness from eating. Therefore, the researchers suggest, protein is pivotal in regulating body weight because of its key role in dietary thermogenesis–related satiety.
Brown Adipose Tissue
Brown adipose tissue is like fat tissue except that it also possesses a thermogenic property: That is, it can take the energy from food and convert it into heat. About 5 percent of the body tissue of human infants is brown adipose, but this number decreases as a person ages. This reduction could contribute to a decrease in dietary thermogenesis as one ages.