By Erica Lesperance, RD, LD

Some people don’t pay much attention to what they eat, or even seem to eat a lot, but are still thin. Others struggle with their weight despite a conscious effort to make healthy food choices and refrain from overeating. This disparity is caused in part by differences in metabolic rate. Some people burn calories faster than others. But eventually we all face the same fate as we age: Our metabolic rate gradually slows down, making it more difficult to maintain a healthy weight.

What Is a Metabolic Rate?

When people talk about having a slow or fast “metabolism,” they are referring to their Basal Metabolic Rate (BMR). Your BMR is the number of calories you burn to fuel all essential body processes and keep your organs and tissues in working order. Your body requires calories to breathe, pump your heart, generate body heat, perspire, transmit messages to your brain, and produce thousands of body chemicals. Add the amount of calories you burn through activity each day to equal the number of calories you need to eat to maintain your weight.

What Happens as You Age?

Many people who did not have any trouble maintaining a normal weight during their 20s and 30s find themselves struggling with weight in their 40s and 50s. The following are several factors that contribute to age-related weight gain.

• Changes in basic body processes
In general, your body runs slower as you get older. Basic body processes don’t require as much energy, which lowers your BMR.

• Less activity
Muscle requires more energy to maintain than body fat does. Therefore, the more muscle you have, the higher your BMR. But people tend to be less physically active in their 40s and 50s than they were in their younger years. With less physical activity, muscle mass decreases, lowering the number of calories needed.

• No change in appetite
Unfortunately, there is not an age-related decline in appetite to accompany the reduced calorie needs. If you eat the same amount as you did before, in the face of a slowing BMR, you will gain weight.

• Hormonal changes
With age, men experience a gradual decline in the hormone testosterone. Less testosterone in men has been shown to reduce muscle, causing the BMR to decline. Postmenopausal women may experience a similar effect from lack of estrogen. Animal studies have shown that a lack of estrogen leads to excessive weight gain, although the exact mechanisms are not yet understood.

• Altered habits
There is a certain freedom that comes with aging. For many, the kids are out of the house and are no longer a financial burden. You may have spent many years cooking dinner each night for your family, but now you are finding you have more freedom, and money, to eat out. While you should certainly enjoy this stage in your life, eating out frequently can result in excessive calorie intake if you are not careful.

What Can You Do?

Is weight gain something you just have to deal with as you get older? Absolutely not! The following are some tips for battling the bulge:

• Activity is the answer
Regular physical activity is the single most effective way to slow the natural decline of your BMR. No matter what your age, it’s never too late to get moving. Aside from burning calories, exercise minimizes muscle loss and keeps muscles strong. Depending on the length and intensity of exercise, a physical workout can boost your BMR for several hours afterward. Therefore, aim for at least 30 minutes of moderate physical activity everyday. In addition, try strength training, as it stimulates the development of muscle, which will raise your BMR. Be sure to consult your doctor before starting a new exercise program.

• Don’t ignore diet
You will need to adjust your calorie intake to make sure you are not eating more than you are burning. Choose foods that are low in fat and high in fiber, such as fruits and vegetables, as they are filling without providing a lot of calories.

• Eat small, frequent meals
Eat a combination of protein, complex carbohydrates, and fat in each of 5 to 6 small meals per day. This provides a continuous supply of nutrients to the body and speeds up your BMR. In addition, it minimizes cravings and the risk of binges that result from not eating often enough.

• Don’t overdo the calorie restriction
Work with your doctor or dietitian to figure out how many calories you need to reach your goals, and don’t try to eat less. As a general rule, you should not eat fewer than 1200 calories per day. Cutting calories too much will only cause a further reduction in metabolic rate.

The Same Old Story
When it comes to maintaining a healthy weight, many look for quick fixes, but the answer always lies in diet and exercise. Preventing age-related weight gain is no different. Start now by assessing your current exercise and eating habits and making improvements where necessary. Even if you have not yet noticed signs of a slowing BMR, such as difficulty maintaining your normal weight, you should still prepare yourself for what is to come.

*This article is intended for general information purposes only, is not individual-specific, nor is it intended to replace the advice of your healthcare team.