What is Basal Metabolic Rate and Why is it important?

Updated: Feb 18, 2021

Many people believe you are only burning calories when you are exercising or active. However, that could not be farther from the truth. It can actually be a pretty dangerous train of thought. You actually expend the most calories when you are physically at rest.

Exercise actually accounts for very little of the Total Daily Energy Expenditure (TDEE). Activity uses 15-30% of the calories expended. That’s all activity not just planned exercise; walking to and from meetings, typing on your computer, playing with your kids. That all counts towards the energy expended throughout the day!

Then, we actually burn calories from the foods we eat! That’s pretty cool, right? This is called the Thermic Effect of Feeding and it accounts for 10% of TDEE. Some foods have a higher Thermic Effect of Feeding than others. For example, if you eat 100g of peanuts vs. 100g of peanut butter, the peanuts are going to have a higher Thermic Effect of Feeding. This is because our body has to breakdown the peanuts more than the peanut butter.

Basal Metabolic Rate is also referred to as Resting Metabolic Rate, but no matter what you call it, it is the show stopper. You burn 60-75% of the calories expended during complete rest! Just staying alive uses most of the calories! However, when you think about it, just because you’re not moving doesn’t mean your body isn’t at work!

There are lots of things going on inside that we aren’t consciously aware of. Our heart is pumping blood. Our digestive system is processing the food we eat. Our lungs are taking in oxygen. Our brain is controlling all of those processes. This all factors into the Basal Metabolic Rate along with the work of our other organs, as well as the nervous system and circulatory system.

Some people have a high Basal Metabolic Rate and some people have a low Basal Metabolic Rate. There are a few things that can effect a person’s BMR. Those include the percentage of lean body mass, age, and thyroid hormone production. BMR decreases 2% for men per decade of age and 3% for women per decade. This happens because as we age we lose lean body mass. Prolonged (especially, extreme) dieting can cause BMR to deregulate which only makes it harder to lose weight! Most of these things are out of our control, but there are a couple that are not.

While we cannot control our age (would it not be amazing if we could?) or our thyroid, without medication, we can control our lean body mass and how we attempt to lose weight. There are safe ways to lose weight, which will not effect your BMR. A Nutrition Coach can help you with the healthiest way to lose weight so you do not do damage (sometimes, irreversible) to your Basal Metabolic Rate.


Kat, Barefield, et al. “Energy Balance and Metabolism.” NASM, 2020,

#nutrition #basalmetabolicrate #thermiceffectoffeeding #TDEE

22 views0 comments

Recent Posts

See All