Thermic Effect of Food
TEF is the amount of calories that it takes your body to digest, absorb, and metabolize your ingested food intake. This makes up about 5 to 15% of your total daily calorie expenditure. Since the metabolic rate is elevated via this mechanism 10 to 15% for one to four hours after a meal, the more meals you eat per day, the faster your metabolic rate will be. This is a good thing, though. It's far better to keep the metabolism high and eat above that level, than to allow the metabolism to slow down by eating infrequently. Protein tends to increase TEF to a rate double that of carbs and almost triple that of fats so that's one of the reasons why I'm a big fan of protein meals.
Determining the Thermic Effect of Food:
To determine the TEF, you need to multiply your original RMR value (2400 in my case) by 0.10 for a moderate protein diet or 0.15 for a high protein diet. So this is what the formula looks like:
TEF = RMR x 0.10 for moderate protein diet (1 gram per pound of bodyweight)
TEF = RMR x 0.15 for high protein diet (more than 1 gram per pound of bodyweight)
Since I eat a very high protein diet (about 350 to 400 grams per day), I use the 0.15 factor and my TEF is about 360 calories per day as displayed by the calculation below:
Thermic Effect of Food = 2400 calories x 0.15 = 360 calories per day
Now add that to your calorie total.
Lähde:
http://www.t-nation.com/free_online..._nutrition_bodybuilding/massive_eating_part_1