Every physiological process that occurs in your body uses energy. Keeping your heart beating and circulating blood uses energy. Creating new body cells requires energy. So does breathing. Even thinking burns calories. Digestion is no exception. The mechanical breakdown and absorption of food requires a substantial number of calories.
Some of the calories in the foods you eat are burned off just to digest them, so the net amount of calories absorbed is actually less than the amount contained in the food. This process has several names such as “Dietary-induced thermogenesis,” the “Specific– dynamic action of food,” or most commonly, the “Thermic effect of food.” The thermic effect peaks about an hour after each meal and begins to drop about three hours after the meal has been completely digested.
You may have heard the expression, “negative calories.” This refers to certain foods, such as asparagus or lettuce, which have a high thermic effect and a low calorie density. It’s almost impossible for these foods to be stored as fat because most of their calories are burned off just to digest them!
When fat loss is your goal, your diet should be heavy in foods with a high thermic effect, including fibrous vegetables and lean proteins. You’ll never get fat eating lean proteins and green vegetables/salads –it’s virtually impossible. Lean protein foods like chicken breast, fish and egg whites have the highest thermic effect of all and that’s why this program is centered on protein, with carbohydrates built around the protein. Lean protein is a “metabolic stimulator.”
The magnitude of the thermic effect can vary from 3% to 30%. Protein foods elicit a thermic effect of up to 30% of the meal's total calories. Natural starchy and fibrous carbohydrates are a close second at around 20%. Fats and refined carbohydrates have a very low thermic effect (fats only elicit a 3% thermic effect). This is one of the reasons dietary fat is so easily stored as body fat.
The fact that dietary fats have only a 3% thermic effect is an important point. There has been a trend in recent years away from high-carbohydrate, low-fat diets towards eating higher fat and higher protein with fewer carbohydrates. To a point, this is
a step in the right direction, but the more fat you eat beyond what you need for your essential fatty acid needs, the slower your metabolism becomes. One reason why diets promoting high fat (above 30% of daily calories) are ineffective is because high fat diets are not thermic!
The promoters of high-fat diets suggest you can eat unlimited fat as long as your carbohydrates are restricted. They also suggest that high fat will stimulate the testosterone and growth hormone release that’s necessary for muscle development and fat burning.
The problem is, even if there’s an extra release of anabolic hormones, it’s not going to help you much if your metabolism is as slow as molasses in January.
You’ll get more detailed instructions on how to create meals with the highest thermic effect in upcoming chapters. For now, you should understand this: Eating every three hours = high thermic effect/fast metabolism. Missing meals = no thermic effect/slow metabolism.
Once you understand the concept of dietary thermogenesis, you’ll never want to miss a meal again because you’ll realize that eating properly increases your metabolism and gets you leaner, while skipping meals slows down your metabolism and makes you fatter!
Nicely written, but I didn’t see an argument for eating frequently during the day. Was that the point of the article or was it to bust the myth that eating more often burns more calories? Since TEF is a percentage, it doesn’t really matter if you eat 10 time per day or 3. You can never burn more than a certain percentage that is dependent on your diet and some other factors, such as time of day. It’s best to stick to something like a low carb diet that has more than double the TEF of Keto, for example. You can use a calculator to compare, like this one.
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