How to Fire Up Your Metabolism

Muscle is active tissue and burns calories, whereas fat burns very few. The more muscle you have, the more calories you burn, even at rest. Learn more.

What is metabolism?

Metabolism is the complex set of chemical processes that convert what you eat and drink into the energy your body needs to function. You need energy (calories) for everything you do, including basic functions like breathing, thinking, repairing cells, and circulating blood.

Your basal metabolic rate is the number of calories your body needs to carry out biological functions, even when you are at rest. They use about 60 to 70 percent of the calories you burn every day.

Exercise and other activities that involve movement, such as cleaning house or gardening, account for another 20 to 30 percent of the calories you burn daily. The final 10 percent is the energy required to digest your food and transport, absorb, and store its nutrients, also known as thermogenesis.

As you age, the amount of energy you expend both at rest and during activity decreases. A primary reason is lost muscle mass. Muscle is active tissue and burns calories, whereas fat burns very few. The more muscle you have, the more calories you burn, even at rest.

People lose approximately one pound of muscle mass a year after the age of 50. Unless you consume fewer calories, fat cells expand, producing the classic middle-age bulge.

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How can you fight back?

Weight gain doesn’t have to be inevitable. You can stay trim, or at least trimmer. More importantly, you want to stay as fit and muscular as you can for the sake of happy, healthful aging. 

• Strength training. By far the most effective way to avoid middle age weight is to hit the weights. Lifting weights builds (or rebuilds) muscle and can boost your metabolism.
• Aerobic exercise. Although aerobic exercise is less effective at building muscle, it can ramp up your metabolism for a period of time after your workout. The most effective way to get this “afterburn” effect is to engage in some kind of high intensity interval training (HIIT). HIIT is simply alternating short bursts of intense effort with longer recovery periods. You can develop a HIIT routine for running, swimming, cycling, or rowing, or come up with your own variation.
• Diet. Make sure you’re getting an appropriate amount of high-quality protein for your age, weight, and activity level. The amino acids in protein are what your body uses to rebuild muscle after you’ve been working out. Your body also works harder to digest it, which in turn burns more calories. According to long-standing guidelines, you should be getting between 10 and 35 percent of your total daily calories from protein. If you are consuming a 2,000 calorie-a-day diet, that’s between 200 and 700 calories a day.
• Stay hydrated. Drinking water increases your metabolism. If the water is cold, you could increase your metabolism by about 3 percent for the next 90 minutes. Room-temperature water has a slightly lower effect. Beyond that, your body needs water for just about everything, and dehydration can slow down processes like digestion and other chemical reactions in your body. It’s even better if you drink water instead of a beverage with calories.

What to avoid

Although it may seem like significantly restricting your calories would be a good way to lose weight, the strategy can backfire. According to the National Institutes of Health, women should eat no fewer than 1,200 calories a day, and men should eat no fewer than 1,500 calories per day. Consuming fewer than those amounts can put you at risk for malnutrition.  

When you lose weight too fast, you also lose muscle, which defeats the goal. Most important, though, eating too little slows your metabolism way down. Your body thinks it’s starving, so it goes into conservation mode.

Bottom line

Your first-line strategy for weight loss should be eating a reasonable number of calories — portion size is important — in a diet with plenty of vegetables and fruits, lean meats, whole grains, and healthy fats.

Building muscle is important for many health reasons, and it could possibly help weight loss. Make sure you are doing a variety of moderate intensity workouts, and be sure to include two to three days of strength training every week.

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