How to burn more calories and control your weight as you get older

Have you ever wondered why you keep getting heavier even though you exercise and watch your diet? Perhaps you have a friend who eats dessert every night and never gains an ounce, whereas you seem to put on more weight every year.

The answer rests in your metabolism: your body's conversion of what you eat and drink into either energy or stored fat. Unfortunately, your metabolism tends to slow down in your 30s - which makes avoiding weight gain in later years an uphill battle. The good news is that no matter what your age or how fit you are, you can take steps to speed up your metabolism.

Three ways you burn calories

Everyone needs a different number of calories to maintain his or her weight. Your body's caloric requirements depend on three factors, all of which can be altered: resting metabolic rate, physical activity and how you process food.

Resting metabolic rate. You burn calories even when you're sleeping, reading or watching television because your body needs energy to carry out basic functions, such as breathing, pumping blood and repairing cells. The number of calories your body uses at rest - known as your resting metabolic rate - accounts for 65 to 75 percent of the calories you use each day.

Several factors affect your body's resting metabolic rate. Men burn more calories than women, heavier people burn more calories than lighter ones - even though they remain heavier - and young adults burn more calories than older adults. In fact, your resting metabolic rate decreases by about 10 percent per decade after age 30.

Some of this age-related decline is caused by the inevitable slowing of metabolic processes. But most of it can be attributed to the gradual replacement of muscle with fat, which burns fewer calories per pound.

Physical activity. Your body in motion burns about 15 to 30 percent of your daily calories. Some physical activity is in the form of exercise: perhaps a bike ride or a session on the treadmill. But much of it comes from everyday activities such as gardening, cooking, walking and even fidgeting.

Processing of food. The remaining 5 to 10 percent of your calories is burned while digesting, absorbing, transporting, and storing what you consume. The energy required for this process is referred to as the thermic effect of food.

Expert's Viewpoint

Carmen Roberts, M.S., R.D. Dietitian, Johns Hopkins Bayview Medical Center

Although you may assume that exercise is the main variable in how many calories you burn, it's actually your resting metabolic rate that accounts for the majority of your daily energy requirement. Your resting metabolic rate slows as you get older and lose muscle mass.

Fortunately, you can build muscle through activities such as strength training, yoga and Pilates. Muscle-building exercises should be done in addition to cardiovascular exercise, which you need to keep your heart and blood vessels healthy.

The U.S. Food and Drug Administration (FDA) cautions about the potential dangers of using body building products that contain anabolic steroids or steroid-like products - including serious liver damage, increased heart attack and stroke risk, and others. The FDA also warns against using powdered pure caffeine, which can cause serious side effects and death. Talk to your health care provider before taking any dietary supplements.

Source: Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50; Updated by Remedy Health Media

Publication Review By: the Editorial Staff at

Published: 08 Jul 2013

Last Modified: 19 Mar 2015