Many people like to blame their weight on their metabolism, the rate at which the body burns calories. Diet and exercise can increase your metabolic rate, and doing so can contribute to weight loss. But maintaining a lower weight will be an ongoing struggle because the metabolism you were born with does not remain boosted without constant effort.
“For most people, whatever lifestyle changes you made to lose the weight, you will have to continue well beyond the period of weight loss in order to keep it off,” says Michael Rosenbaum, MD, associate professor of clinical pediatrics and clinical medicine at Columbia University Medical College in New York. “People who are able to keep the weight off in general have to reinvent themselves.”
In fact, your metabolism is built to resist rapid weight loss, which in centuries past meant that if food ran out, your body could switch to survival mode by lowering metabolism. “That biology was extremely advantageous to all of our ancestors prior to the Industrial Revolution,” Rosenbaum says. “We’ve worked on it for 300,000 years. We’re pretty good at it. It’s just not good for this environment.”
How Your Metabolism Responds to Weight Loss
Boosting your metabolism through diet and exercise will provide quick weight-loss returns in the beginning, but as you lose weight your metabolism will actually begin to slow down. “There’s a metabolic opposition to keeping the reduced weight,” Rosenbaum says. “In attempts to maintain or lose weight, your body is fighting back. It’s burning calories more efficiently, especially calories you burn through aerobic exercise or activities like walking around.”
This is one of the reasons why people dedicated to a weight-loss program will sometimes encounter a plateau. They have tremendous success in losing weight up to a certain point, but then suddenly stop seeing results. Their metabolism has slowed to match their new level of fitness; there is less body mass to fuel, so the metabolism doesn’t have to work as hard.
Keep in mind, too, that a person who has had to boost their metabolism to lose weight will always have to work harder to keep the weight off than a naturally lean person. “If you have two people who both weigh 150 pounds, but one has lost 150 pounds to get to that weight, the person who is weight-reduced will have to eat 300 to 400 calories less or burn 300 to 400 more calories through exercise every day than the person who is naturally 150 pounds,” Rosenbaum says.
Overcoming Metabolic Resistance to Maintain Weight Loss
The health benefits of weight loss are undeniable. Here’s how you can overcome your metabolism to lose weight and keep it off:
- Reassess your energy balance. You may need to eat even less as you lose weight because your body needs fewer calories to sustain itself. On the other hand, you can increase the intensity and duration of your workouts. Either strategy can help break a fitness plateau.
- Change your fitness routine. Try different types of exercise to work new muscles and keep your body guessing. Strength training in particular is known to help keep your metabolism high, as muscle burns more calories at rest than fat does.
- Change your diet. Complex carbohydrates should make up at least 50 percent of your daily diet, to help keep your body properly fueled. But if you spend a few days eating fewer carbohydrates and more lean protein, the change could bump you off your plateau. It takes more calories for the body to convert protein into fuel than carbohydrates or fats.
Maintaining weight loss will be a long-term struggle against your body’s own survival processes, which always assumes your food supply could run out at any moment. “It’s much harder to keep weight off than to actually lose it, as evidenced by all the people who lose weight quickly only to regain it,” Rosenbaum says. “Over 75 percent of individuals will return to their previous levels of body fatness within a few years following otherwise successful weight loss. This is the result of combined metabolic, behavioral, endocrine, and autonomic nervous system changes that ‘conspire’ to favor the regain of lost weight.”
Advises Rosenbaum, “Our studies indicate that this opposition to sustained weight loss does not diminish over time and is equally potent in overweight and never-overweight individuals. Therefore, long-term lifestyle changes are necessary to sustain weight loss.”