But most diets ultimately fail because you eventually feel hungry and deprived, scrap the plan, and gain back the lost weight (and, in many cases, even more).
It’s no wonder: As your body weight lowers, your metabolism drops, and you need less food every day.
Yet as you restrict how much you eat, your body’s hunger hormones nudge you to eat more. It becomes a physical and psychological struggle that can feel impossible (not to mention miserable). “Food restriction is not a long term solution to obesity,” says obesity researcher James Hill, PhD.
Sure, you need to eat less than you were before. But you should prioritize finding a lower intake that feels satisfying–then make up the difference with exercise.
For example, let’s say you’ve lost 10 percent of your body weight, and you now need 150-200 fewer calories a day to maintain that new weight. You have to fill that gap forever. You could eat 150-200 fewer calories by never having an afternoon snack or eating a very small breakfast—both of which will probably make you hungry.
Or you could increase your activity by 150-200 calories by going for a power walk, taking a fitness class, or biking. “Physical activity should be driving the bus during weight maintenance,” says Hill, Director of the Nutrition Obesity Research Center at the University of Alabama at Birmingham.
How much exercise is enough? For most people, the sweet spot is 60 minutes a day, though some people will need more and some less. Hill, co-founder of the National Weight Control Registry (a registry of people who have successfully lost weight and kept it off), says people in the Registry exercise for an average of an hour a day. And as you’ve heard before, you don’t have to get it all at once. Movement throughout the day adds up too.
Another benefit of exercise: It increases something called “metabolic flexibility”. That’s the ability of your body to easily switch between burning carbs and fat for energy and efficiently use calories. That’s a good thing because being metabolically inflexible can result in insulin resistance, leading to more stored fat and an increased risk for type 2 diabetes. In fact, Hill says there may actually be a threshold where you can become so metabolically inflexible that your body is actively working to gain weight. If that’s the case, he says, exercise is the most effect way to reverse that.
Bottom line: The weight loss journey doesn’t end once you’ve dropped the pounds; to keep them off, you’ll need a plan of action for closing the “energy gap” that’s doable for the long term. Exercise should play the biggest part in that, says Hill. “The more you fill that energy gap with exercise the more successful you are.”
