There are 3 main ways the body uses calories. There’s the energy needed to keep our hearts, brains, and every cell of our body working, known as the basal metabolism. There’s the energy used to break down food, known as the thermic effect of food. And there’s the energy burned off during physical activity — like walking around, fidgeting, or exercising.
The basal metabolic rate (BMR – calories burn at rest) accounts for the largest amount of the total calories a person burns each day (65 to 80 percent for most adults). Physical activity, on the other hand, accounts for a much smaller portion — 10 to 30 percent for most people — despite what many people believe. And digesting food accounts for about 10 percent.
There are several factors that can affect how fast or slow a person’s metabolism. These include the amount of lean muscle mass, body fat % and genetics.
You might not be able to change what your parents give you (genetics) but by lifting weights, you can improve your body composition (more lean muscle mass and less body fat % ). In turn, you will burn more calories and increasing your basal metabolic rate.