GLP-1 weight-loss drugs like Ozempic and Zepbound are so effective it might seem that a person can lose weight without doing anything at all.

But that's a false notion, experts say. Losing weight properly and keeping it off will require lifestyle changes that extend beyond a weekly GLP-1 injection.

"Many patients lose muscle mass in addition to fat mass and have GI symptoms that lead to stopping medication, " senior researcher Dr. JoAnn Manson said in a news release. She's chief of preventive medicine at Brigham and Women's Hospital in Boston.

These potential problems prompted experts to craft a set of diet and exercise tips specifically for people on GLP-1 meds. The suggestions were published in JAMA Internal Medicine.

"We propose an approach to improving outcomes on GLP-1s by preserving lean body mass, ensuring good nutrition, and managing symptoms that can otherwise lead to stopping medications, " Manson said.

For example, lean muscle mass accounts for 25–40% of the weight a person loses when using GLP-1 drugs, experts note.

"Begin each meal with 20 to 30 grams of protein from foods like fish, beans, chickpeas, or tofu, " the recommendations state. "Aim for 1.0 to 1.5 g of protein per kilogram of body weight daily, if moderately active. If your appetite is very low, use protein shakes with at least 20 g protein per serving."

The recommendations also call for two to three half-hour sessions of strength training a week, to help preserve muscle mass.

GLP-1 drugs work in part by reducing a person's appetite, which can interfere with a person properly fueling their bodies, researchers noted.

"Keep your energy by eating smaller meals plus snacks (fruit, a handful of nuts, unsweetened yogurt), " the paper says.

"Choose slowly digested carbohydrates like sweet potatoes or oatmeal instead of refined grains (white bread, pastries) or sugary drinks that can cause blood glucose swings. To feel full longer, add healthy fats like olive oil or avocado to meals."

Overall, people should adopt a well-balanced, nutrient-dense diet to compliment their GLP-1 drug use, experts say. Avoid calorie-restricting diets, which can result in unhealthy weight loss and cause malnutrition by leaving out essential nutrients and vitamins.

When it comes to the potential gastrointestinal (GI) side effects of GLP-1 drugs, experts offer a raft of recommendations:

GLP-1 drugs can cause dehydration, so patients should drink eight to 12 cups of water a day. Eating soups or water-rich fruits and vegetables like cucumbers and watermelon also helps, experts say.

Finally, to keep lost weight off, the experts recommend adopting a regular exercise program. On top of strength training, patients should build to 150 minutes of moderate-intensity exercise a week with activities like brisk walking, bicycling or light yard work.

"Although GLP-1 (drugs) represent a major breakthrough in obesity management, lasting treatment success requires integrating medication with individualized nutrition and physical activity interventions, " the authors write.

"This comprehensive approach optimizes sustained weight loss while mitigating side effects, preserving muscle mass, and limiting nutritional deficiencies, " they add.

More information: Farhad Mehrtash et al, I Am Taking a GLP-1 Weight-Loss Medication—What Should I Know?, JAMA Internal Medicine (2025). DOI: 10.1001/jamainternmed.2025.1133  Journal information: JAMA Internal Medicine

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