Ask the Dietitian: How Do You Combat a Slowing Metabolism?

Metabolism is what influences your body’s basic resting rate energy needs. But when it comes to weight loss, the main factors for success include how many calories you consume and your physical activity levels. Even at rest, your body burns energy to maintain internal functions (i.e., blood circulation, muscle repair, cell generation and repair, balancing hormones, etc.) The number of calories your body needs to carry out these internal basic functions is your metabolism, also called your basal metabolic rate — and it’s not something you can control.

Here, a look at how the body burns energy, how metabolism changes as you age and what you can do to prevent weight gain later in life:

There are three main ways the body burns energy:

• Basal metabolism (see above)
• Thermic Effect of Food (energy used to break down food)
• Energy used in physical activity

Basal metabolism accounts for about 60–80% of our ability to burn calories in a day. Energy used to breakdown food accounts for about 10%, and physical activity accounts for anywhere from 10–30% (30% being limited to extreme athletes).

While basal metabolism doesn’t slow down with age, many people become less physically active. It’s also common to lose lean muscle mass and correspondingly replace it with fat as you age. The lean muscle mass of a typical young adult makes up about 50% of total body weight, which drops to about 25% of total body weight between 75–80 years old. It takes more energy (meaning more calorie burn) to maintain muscle than it does fat. That’s because less muscle corresponds to slower metabolism.

Still, metabolism is different for every individual, and science cannot exactly explain why your best friend can eat larger portions and not gain weight while you track your meals more closely and work out daily.

While everyone is different, there are still universal tips that can help prevent weight gain and a declining metabolism as you age:

• Be more physically active. Try to work in more activity daily, whether it’s taking the stairs, getting up every hour to go for a brief walk or trying a new workout class.
• Focus on building muscle with strength-training workouts. Muscle tissue burns more energy than fat tissue when the body is at rest. People who have built up more lean muscle tissue have higher resting metabolic rates than those with more fat tissue.
• Don’t follow fad diets. Dieting and extreme weight loss (and the yo-yoing that often occurs) actually causes a downregulation in metabolic rates. That’s because when you lose weight, you not only decrease your fat mass, but also your muscle mass. While cutting calories is OK — especially if weight loss is the goal — keep in mind it’s also important to continue to build muscle mass and maintain physical activity.
• Find healthy lifestyle habits you can keep up over long periods of time. For example, track what you eat and regularly record what you weigh. Research from the National Weight Control Registry found people who are most successful in losing weight and keeping it off weigh themselves regularly, count calories and exercise regularly.
• Know what motivates you. Set SMART goals and surround yourself with people who are like-minded and supportive.
• Listen to your hunger signals. Practice mindful eating so you don’t consume excess calories when you might be bored or stressed.

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