All food that we consume uses calories aka energy to break down and metabolize it so that we can use it in our body. How many calories this uses is called the “thermal effect” of the food. Macronutrients fall under three categories and they each have different thermal effects. Any food that is harder to break down will have a better thermal effect. This refers to any solid food; liquids and liquefied food have a much lower thermal effect, as it is already quite broken down and easier for the body to metabolize and absorb.


Protein is the best macronutrient for its thermal effect and burns around 30 calories per 100 consumed according to Live Long Stay Young. Protein must be chewed more than any other macronutrient and takes longer to break down in the stomach compared to other macronutrients. This means you use more energy to break down protein ready for it to be absorbed into your bloodstream for the body to use. Another great plus of consuming more protein is how long it takes to break down, meaning your stomach is fuller for longer. This means not only does it have the highest thermal effect but you are less likely to want to snack as you should feel fuller for longer.


Carbohydrates are extremely vital for our diet and we should never cut them out. Carbohydrates have many great benefits, especially for our bone health. There are many carbohydrates and they can range from having a thermal effect of 5% to 15%. This is mostly explained by the indigestible fiber found in carbohydrates such as whole grain foods, nuts, and seeds. There are some carbohydrates that are said to have a negative calorie balance. One of the most well-known of these is celery, which is said to use more calories to break down than it contains, although this hasn’t been scientifically proven.


Fats are the worst macronutrients in terms of their thermal effect, but this does not mean we don’t still need them. This is because we usually use fats as they come into the body, so less are broken down into other sources. Fats have a thermal effect of 0-5% and this can also depend on how much fat you have already consumed in the day. Although fats have the smallest thermal effect, they are still extremely important to consume in moderation, as they give the body energy to break down foods in the first place and they are vital for cell growth. There are some fats that are better than others, therefore, you should try and stick to the fats that are the best for your body.

To be our healthiest, our body needs all three macronutrients so that it can work at its best and function properly. If you are trying to lose weight, follow a nutritional plan, speak to a personal trainer or your doctor, and never cut out a macronutrient- we need each of them or our body will suffer in the long run.