Thermic Effect Of Fat And Carbohydrates

Fat and carbohydrates provide the most energy for most individuals, and protein and alcohol are also sources of energy. If you are trying to lose weight by taking advantage of the thermic effect of foods, you may be wondering if you should emphasize or reduce your intake of fat and carbohydrates. For most individuals, however, the healthiest method of controlling weight is to eat a variety of nutrient-dense foods in moderation.

Calorie Balance

If you eat more calories than you burn, you will gain weight, and if your calorie intake equals your calorie expenditure, you will maintain your current weight. You can create a calorie deficit to lose weight by eating less or increasing your expenditure, and you will lose about 1 pound of body fat with each deficit of 3,500 calories, according to the Centers for Disease Control and Prevention. Foods with a higher thermic effect can increase your calorie expenditure slightly, and fat and carbohydrates have a lower thermic effect than proteins, according to the National Academies Press.

Thermogenesis and Metabolism

About 60 to 75 percent of total energy expenditure is due to your basal metabolic rate, or energy needed for basic functions such as breathing and keeping your heart beating, according to MayoClinic.com. Physical activity, including planned exercise and spontaneous movements, also burns calories. Thermogenesis, or the energy for metabolizing your food, requires about 10 percent of your total calories. Changes in your diet, such as substituting protein for fat or carbohydrates, can increase thermogenesis, or the thermic effect of food. The result probably would not be enough for a significant impact on your weight.

Calories Burned

The thermic effect of fat is about 0 to 5 percent of the calories it provides, according to National Academies Press. For carbohydrates, the thermic effect ranges from about 5 to 10 percent of calories. This means that you would burn about 0 to 25 calories per day if you ate 500 calories from fat, or about 25 percent of the total calories on a 2,000-calorie diet from fat. If you eat 1,000 calories from carbohydrates, or get 50 percent of the calories on a 2,000-calorie diet from carbohydrates, your thermic effect from carbohydrates would be 50 to 100 calories.

Comparison to Protein

The thermic effect of protein is 10 to 20 percent of calories, according to the National Academies Press. This value is higher than the thermic effect of fat and carbohydrates because of the extra energy needed to break down protein into amino acids and glucose, and to synthesize new proteins in your body. Individuals who eat a high-protein diet burn off more calories than individuals who eat a high-fat diet, according to a review article by Klaas Westerterp published in "Nutrition and Metabolism."