You would give up just about anything to be the same weight you were when you were younger, right? Believe it or not, you need give up anything. That is, as long as you keep doing what you’ve always done—and maybe a bit more.

Other factors

Although metabolism plays a large role in controlling weight, it can’t take all the blame. Genetics play a role, too. But genetics are predetermined, and lifestyle is not.

Metabolism is the amount of energy—in this case, calories—that the body burns to maintain itself. You’re always burning calories, even when you’re sleeping. Your basal metabolic rate (BMR) is the number of calories your body uses at rest. How many calories you burn depends on your BMR, exercise, and the body’s muscle-to-fat ratio. Muscle cells burn more calories than fat cells. Muscular people, with less body fat, have a higher metabolism.

After the age of 45, it is estimated that the average person loses around 1 percent of muscle mass per year. To compensate, you may need to become more active than you once were.

Changing with age

Resting metabolic rate regulates body weight and body composition and daily energy needs. Resting metabolic rate decreases with age in women.

If you consume more calories than you burn, the excess is stored as fat and weight gain occurs. According to the CDC, a one-pound weight loss represents about 3,500 calories. For a weight loss of one to two pounds per week, caloric intake needs to decrease by 500 to 1,000 calories every day.

To jump-start your metabolism, you must regain the muscle mass. The most efficient way to do that is regular exercise.