Ok, so in simple terms here’s what you need to know about the thermic effect of food
Some of the calories in the foods you eat are burned off during the digestion process, so the net amount of calories absorbed by your body is actually less than the amount contained in the food. This process is commonly referred to as the thermic effect of food (TEF).
Foods with a high TEF will increase your metabolic rate because your body has to work harder to digest, process and utilize the food.
Lean proteins and fibrous complex carbs are the two food groups that have a higher thermic effect and will increase your metabolic rate more than any other type of food.
Lean protein foods, ie chicken breast, fish and egg whites have the highest thermic effect at around 30%. So, for every 100 calories of chicken breast you eat, almost 30 of those calories are burned just to digest it. Therefore, the net caloric value is only about 70 calories.
Fibrous complex carbohydrates, such as broccoli, whole grains, brown rice, beans and oatmeal, also have a high thermic effect of around 20%.
Simple carbohydrates like suger and refined carbohydrates are very easily digested and turned into energy by your body. Therefore they burn very little energy in digestion. These types of foods are so easy for our bodies to digest that they only require an estimated 3% of the calories you take in
Fats have the lowest thermic effect, only around 3%, but when chosen properly, fat can be your best ally in the war on body fat, The best fats come from unsaturated Essential Fatty Acids. Eat more liquid fats and stay away from solid fats
If you consume too much of any food, it will be stored as body fat. But lean protein foods and fiber-containing complex carbohydrates, due to their high thermic effect, are less likely to be converted to body fat than other types of food.
So if you’re trying to lose body fat, you should be eating several small, healthy meals throughout the day that consist primarily of foods with a high thermic effect. Eat Protein , complex carbs and fibrous veggies and stay away from simple carbs