Thermic Effect Of Food: What It Is And How It Works

Throughout the Rebuild Health and Fitness podcast, and online, we often discuss the thermic effect of food, when pertaining to nutrition information, calorie deficits and body composition. But what is the thermic effect of food? And how does it work? 

Technically speaking, it refers to the amount of energy your body takes to absorb, digest, and metabolise the food you consume. So, when you consume calories, some foods are harder to digest, therefore your body expends more energy in the process, the thermic effect of food.

A calorie is a calorie. A calorie is a unit of measurement for food energy. By definition, it is the amount of heat required to raise the temperature of 1g water by 1°C. This is measured through a bomb calorimeter.

Some foods have higher or different nutrients, some have a higher energy density. 

For example, an apple is high nutrient, low energy, whereas a lolly is  low nutrient, high energy.

Fat loss, maintenance, or weight gain comes down to energy in versus energy out. If you want to lose fat, you need to create an energy deficit. Keep in mind, however, this does not translate into all calories being the same.

Eating 2000 calories of donuts and 2000 calories of chicken will not give you the same end result even if you’re in a calorie deficit.

Why?
 
In simple terms, it takes energy to digest foods. Some foods have a higher thermic effect, meaning you can create a bigger deficit eating certain foods. The thermic effect of food differs with different macronutrients and protein has the highest thermic effect. 

So, if you ate 2000 calories of donuts and 2000 calories of chicken, you would create a bigger energy deficit eating the chicken because of the thermic effect of the food.

That being said, the overall energy is what is most important. So even though you could eat anything at all and lose fat, you can make it easier by focusing on what you are eating. 

To summarise: