If you spend any time reading about diets and weight loss, or if you are on a quest to lose weight, no doubt the issue of your metabolism has come up. Many people who are overweight blame a slow metabolism, and so part of the goal in achieving weight loss becomes improving it.
Metabolism is the complex set of chemical processes that convert what you eat and drink into the energy your body needs to function. Although you need energy (calories) to exercise and perform other activities, your body also needs energy to carry out its “hidden” functions like breathing, thinking, repairing cells, and circulating blood. Your basal metabolic rate is the number of calories your body needs to carry out these functions, even when you are at rest. Performing these basic functions accounts for about 60 to 70 percent of the calories you burn every day.
Two additional factors determine how many calories you burn in a day. Exercise and other activities — cleaning house, gardening, other types of movement — account for 20 to 30 percent of your daily calories burned. 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 for this slowing is lost muscle mass. People lose approximately one pound of muscle mass per year after the age of 50. As this slowing occurs, unless you are adjusting your caloric intake accordingly, the muscle is replaced with fat (as fat cells expand), which accounts for much of the weight gain many of us see in middle age.
Weight gain doesn’t have to be inevitable. There are things you can do to fight it.
Strength training. By far the most effective way to forestall the onset of the middle-aged bulge is to hit the weights. Lifting weights builds (or rebuilds) muscle. 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. According to the Centers for Disease Control and Prevention, strength training can provide up to a 15 percent increase in your metabolic rate.
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 has to work harder to digest it, which in turn burns more calories. According to the 2010 Dietary Guidelines for Americans, 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. One study showed that drinking just 500 milliliters (a little more than 2 cups) of water increased energy expenditure by 24 percent for 60 minutes after it was consumed. Beyond that, your body needs water for just about everything, and being dehydrated can slow down processes like digestion and other chemical reactions in your body.
Although it may seem like significantly restricting your calories would be a good way to lose weight, this 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 these amounts can put you at risk for malnutrition because it’s hard to get enough of the essential vitamins and minerals you need from food, assuming you’re eating a healthy diet. Additionally, when you lose weight too fast, you also lose muscle, which defeats the goal. Most important, though, eating too little actually slows your metabolism way down. Your body thinks it’s starving, so it goes into conservation mode.
If you’re looking to boost your metabolism because you want to lose weight, it’s best to take a balanced and common-sense approach. Eating a balanced diet with plenty of vegetables and fruits, lean meats, whole grains, and healthy fats should be your first-line strategy for weight loss. Exercise is important for many health reasons, being an effective tool for weight loss among them. 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.
November 30, 2015
Janet O’Dell, RN