THURSDAY, April 4, 2019 (HealthDay News) -- If you've lost a bunch of weight and want to keep those pounds from piling back on, you'll need to make regular physical activity a part of your life.
New research looking at people who lost 30 pounds or more and kept it off for a year or longer found that regular exercise was key.
"These people rely on physical activity to maintain their weight rather than restricting calorie intake. This shows how critical physical activity is for maintaining weight," said lead author Danielle Ostendorf. She's a postdoctoral fellow at the University of Colorado Anschutz Health and Wellness Center.
But Ostendorf was quick to point out these findings don't mean that people shouldn't pay attention to their diet. "Diet is very important, especially for weight loss," she said.
To lose weight, you need to eat fewer calories than you use during the day, according to the U.S. Centers for Disease Control and Prevention. The number of calories someone needs depends on several factors, including age and activity level.
Generally, a 40-year-old woman needs between 1,800 and 2,200 calories a day, the U.S. government's dietary guidelines recommend. A man the same age usually needs about 2,400 to 3,000 calories daily. The more you move, the more calories you can eat.
The current study looked at three groups of people.
The weight maintainer group included 25 adults who had lost about 30 pounds or more and kept it off for more than a year. Another group included 27 adults at a normal weight. The final group had 28 adults who were either overweight or obese.
All three groups were monitored over a week while they were living as normal. No one gained or lost weight.
The volunteers weren't given any specific instructions on diet or exercise. They gave urine samples at the beginning and end of the study to measure how many calories they used (energy expenditure).
Each participant also wore a fitness device to measure their activity. It could differentiate whether people were standing or stepping and determine intensity level, Ostendorf said.
The study found that people who maintained their weight loss burned about 180 more calories a day during physical activity than other participants.
People who are overweight and obese use more calories normally, just to move a larger body throughout the day, the researchers explained. So, the fact that the maintainers used more calories than people who were still overweight or obese suggests they were more physically active.
Data from the fitness devices suggested the same. Maintainers clocked about 12,000 steps per day. Normal-weight adults had about 9,000 steps daily, and those who were overweight or obese had 6,500.
The maintainers spent about 95 minutes a day doing moderate to vigorous activity, Ostendorf said. Moderate activity might be walking up a hill; you can still talk but you might be a little out of breath. Running is an example of vigorous activity, she said.
Compared to the normal-weight group, both the maintainers and the overweight and obese group ate and used 300 calories more a day. But the maintainers appeared to compensate with more activity, researchers said.
The takeaway: You have to be active to stay at a healthy weight.
"People can lose weight and maintain the weight loss. There are people who have done this successfully. And it doesn't have to be an extreme workout," Ostendorf said.
Current U.S. physical activity guidelines call for at least 150 to 300 minutes weekly of moderate-intensity activity. Any physical activity counts toward that goal.
Dana Angelo White, a registered dietitian and clinical assistant professor of athletic training and sports medicine at Quinnipiac University in Hamden, Conn., agreed with the study's conclusion.
"If you manage to successfully lose weight, there's a certain level of maintenance required. And, you can't just rely on diet or exercise by themselves," said White, who wasn't involved with the study.
She emphasized that everyone -- regardless of weight status -- needs to be physically active for good health.
"Commit to moving more. That doesn't mean you need to go from zero to a hundred overnight. But find some sort of enjoyable exercise routine, and increase your activity outside of exercise as well. Make extra steps wherever you can. Walk around on your lunch break, or if you can, walk your kids to school. Anything to keep moving," White suggested.
The study was published in the March issue of Obesity.
Learn more about the importance of exercise from the American Heart Association.