All About Metabolism | Everyday Health

People often refer to metabolism as being fast or slow, which means how quickly the body works through the energy conversion process. “We usually see patients coming to us saying, ‘My metabolism is down. My metabolism is slow,’” Dr. Griebeler says. “That’s related to the basal metabolic rate (BMR), which is the resting metabolic rate.”

BMR refers to the minimum number of calories your body needs to survive when at rest and accounts for roughly 60 to 70 percent of your body’s overall energy needs, according to the Cleveland Clinic. This varies from person to person and isn’t steady over one’s lifetime either — it can decrease if you lose weight quickly or eat too few calories, which results in weight loss stalling. The higher your BMR, the more calories you burn, even when at rest.

Griebeler says that the calories burned by daily living and doing things like sitting, eating, and breathing are referred to as nonexercise activity thermogenesis. “The average person with minimal physical activity needs about 10 calories per pound of body weight to maintain their daily functions and remain the same weight,” says Felix Spiegel, MD, a bariatric surgeon with Memorial Hermann in Houston. “If someone is more active, their metabolism is increased, and they would require more calories.”

According to the Cleveland Clinic, the speed of your metabolism can be affected by several factors:

• Muscle Mass Higher muscle mass translates to a faster metabolism. There’s an opposite relationship between fat and metabolism. “The more fat you carry, the slower your metabolism is generally,” Dr. Spiegel says.
• Age Metabolism naturally slows as you age.
• Sex Men typically have faster metabolisms than women due to higher muscle mass.
• Genetics Your genes determine how much muscle mass your body will have.
• Movement Any type of movement leads to more calories burned than being sedentary.
• Smoking Nicotine stimulates metabolism, leading to more calories burned. That said, the negative health consequences of smoking far outweigh any metabolic benefit.

Many of these factors are out of your control but not all of them. You cannot control your genes, for instance. “It is what it is — some people are fast burners, and some are slow burners,” he says. Physical activity and your muscle mass, however, are within your power. “We can control [metabolism] — it’s important to say that,” Griebeler says.