Exercise may not help you lose as much weight as expected, but it could be one of the keys to keeping it off. A study of more than 1,100 people found that how much someone exercised had little effect on how much weight they first lost, while higher activity after weight loss was strongly linked to maintaining that loss. The same habit is tied to better cholesterol, lower inflammation and steadier blood sugar, so the payoff reaches well past the number on the scale.
What does exercise do during weight loss?
Weight comes off when you take in fewer calories than you burn. Exercise widens that gap, but the extra burn is usually smaller than the plan assumed. A hard session can raise appetite and send you to a bigger meal, and many people sit still more through the rest of the day without noticing, which trims the net calorie cost of the workout. Over several weeks the body also burns slightly fewer calories doing the same activity, a response researchers call metabolic adaptation.
In the study of more than 1,100 people cited in the source, physical activity had little effect on how much weight participants first lost, while higher activity after the loss was strongly linked to holding onto it. That is an association, not proof that exercise on its own will block regain for every person.
Why can exercise help you keep the weight off?
Several measurable changes happen in the body after weight loss, so activity does more to keep weight off than to take it off.
It offsets a drop in resting calorie burn
Resting energy expenditure is the number of calories the body burns at rest. After weight loss it falls by more than the smaller body size alone would predict, which pushes weight back up. Daily activity raises total daily energy expenditure, which can help to partially offset that decline.
It protects muscle, not just fat
Weight loss removes muscle along with fat, and less muscle means a lower resting burn. Researchers at the University of Cambridge note that lean body mass, including muscle, can make up to 40% of total weight lost during drug treatment, according to their analysis published in eClinicalMedicine. Resistance work such as lifting or Pilates can hold or rebuild that muscle.
It keeps the body able to burn fat
Harder exercise can improve fat burning and metabolic flexibility, the ability to switch between burning carbohydrate and fat depending on what is available, so fat burning continues even when calorie intake is low.
It steadies insulin, appetite and mood
Activity is also tied to better sleep, steadier mood and lower stress, which lower cortisol and may reduce fat storage. Regular movement can help regulate appetite and blood glucose, which may cut cravings and overeating for some people who exercise.
What does the research show about weight regain?
In a review of long-term obesity care published in Medical Clinics of North America, a meta-analysis of 29 long-term weight-loss studies found that more than half of lost weight returned within two years and more than 80% by five years. The review argues that lasting results need ongoing clinical attention and counseling aimed specifically at maintenance, not just the initial loss.
The University of Cambridge team modelled what happens after people stop GLP-1 drugs such as Ozempic and Wegovy. A year after stopping, people regained on average 60% of the weight they had lost, after which regain plateaued and they kept off about 25% of the loss. One of the researchers, Brajan Budini, said the drugs "act like brakes on our appetite" and that stopping them is "essentially taking their foot off the brake."
Some individuals are successful at both losing weight and maintaining this weight loss over the long term. In an analysis of 14,306 US adults in the 1999-2006 National Health and Nutrition Examination Survey, 36.6% of those who had ever been overweight or obese kept off at least 5% of their weight for a year, with 17.3% keeping off at least 10%, 8.5% at least 15% and 4.4% at least 20%. Among those holding a 10% loss, the average kept off was 19.1 kilograms (42.1 pounds) and the median was 15.5 kilograms (34.1 pounds). The authors noted these rates ran higher than figures reported in many clinical trials.
The scale of the problem is large: around 40% of US adults aged 20 and older are classed as obese. Age-adjusted rates rose from 22.9% in 1988-1994 to 42.4% in 2017-2018, easing to 40.3% in 2021-2023, according to National Center for Health Statistics data compiled by Pew Research Center.
Which types of exercise may help?
Aerobic activity such as brisk walking, cycling and running burns calories, and at higher intensity it may improve the body’s ability to use fat for fuel. Resistance training such as lifting and Pilates helps build and preserve muscle mass, which supports a higher resting energy expenditure, aiding long-term weight maintenance. People differ in how many calories they burn in a session and whether it leaves them hungry later, so the mix that works is individual.
Can exercise work with weight-loss medication?
Evidence cited in the source suggests that pairing exercise with a weight-loss drug such as Saxenda may help people keep off more weight than the drug alone. The Cambridge work adds context: GLP-1 drugs have produced weight losses of 15 to 20% in clinical trials, but about half of patients stop within the first year and three-quarters within two years, often because of side effects or limits on insurance coverage and prescribing.
What to do now
- Build activity you can keep after you reach your goal weight, since exercise may help you keep weight off more than it helps you take it off.
- Add resistance training such as lifting or Pilates, which can help preserve or even rebuild muscle mass.
- Include aerobic work like brisk walking, cycling or running for calorie burn, with some higher-intensity sessions to support fat use.
- Pay attention to hunger and how much you move across the whole day, not only during the workout.
- If you take Saxenda or another weight-loss drug, ask your clinician how activity should fit your plan both during treatment and after you stop.
FAQ
Is exercise effective for losing weight?
It has only a modest effect on how much you first lose. In a study of more than 1,100 people, physical activity had little effect on initial weight loss, partly because workouts can raise appetite and the body adapts by burning fewer calories over time.
Does exercise help keep weight off?
Yes. After weight loss, more activity helped keep the weight off, likely by offsetting a drop in resting calorie burn, preserving muscle, aiding fat burning and steadying appetite and blood sugar.
How much weight do people regain after stopping weight-loss drugs?
University of Cambridge researchers, in eClinicalMedicine, found people regained on average 60% of lost weight within a year of stopping GLP-1 drugs such as Ozempic and Wegovy, after which regain plateaued and they kept off about 25% of the weight lost.
