Your metabolism constantly provides your body with energy for essential body functions like breathing and digestion. Your body needs a minimum number of calories (the basal metabolic rate or BMR) to sustain these functions. Factors like age, sex, muscle mass and physical activity affect metabolism or BMR.
Metabolism refers to the chemical (metabolic) processes that take place as your body converts foods and drinks into energy. It’s a complex process that combines calories and oxygen to create and release energy. This energy fuels body functions.
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Your metabolism never stops, even when your body is at rest. It constantly provides energy for basic body functions, such as:
Your basal metabolic rate (BMR) refers to the minimum number of calories your body needs to function while you’re resting. This amount varies from person to person. Your BMR fulfills 60% to 70% of the energy your body uses. Rapid weight loss and aggressive calorie restriction decrease your BMR — this is one reason why weight loss is usually not linear and may stall at some point.
Your body uses about one-tenth of its energy to process food into fuel. The remaining energy fuels your physical movement.
Many people blame metabolic problems for weight struggles. But your metabolism naturally regulates itself to meet your body’s needs. It’s rarely the cause of weight gain or loss. In general, anyone who burns more calories than they take in will lose weight.
Someone with a fast metabolism or fast BMR burns a lot of calories even while at rest. If you have a slow metabolism or slow BMR, your body needs fewer calories to keep it going.
A fast metabolism does not necessarily lead to thinness. In fact, studies show that people with overweight/obesity often have fast metabolisms. Their bodies need more energy to keep basic body functions going.
A few people have endocrine disorders that cause their metabolism to work slower. You may burn fewer calories and put on weight if you have:
Metabolism can also cause other systemic health problems. Anyone who takes in more calories than they burn will gain weight. This can lead to obesity and related problems like diabetes and metabolic syndrome.
Metabolic disorders are conditions that affect how the body processes certain nutrients or enzymes. You inherit a metabolic disorder from a parent. How much you eat or exercise isn’t a factor.
Types of inherited metabolic disorders include:
Many factors can affect how your metabolism functions. These include:
These steps may benefit your metabolism:
You should call your healthcare provider if you experience:
A note from Cleveland Clinic
Your metabolism plays a critical role in keeping your body functioning. Certain factors like age, muscle mass and physical activity can affect how your metabolism uses calories for energy. Having a fast or slow metabolism isn’t really a factor in weight gain or loss. Your weight has more to do with calories in versus calories out. Drastically cutting back on calories can have a negative effect on how your metabolism works. Talk to your healthcare provider about other ways to achieve a weight that’s healthy for you.
Last reviewed by a Cleveland Clinic medical professional on 08/30/2021.
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