Why Diet and Exercise Still Matter During Treatment with GLP-1 Medications

A new publication underlines the importance of nutrition and physical activity to ensure patients are successful in their weight loss journeys.

In it, researchers from Mass General Brigham provide advice to reduce side effects, protect muscle health, and ensure sufficient nutrient intake for patients taking GLP-1 medications such as semaglutide (sold as Wegovy for weight loss) or tirzepatide (Zepbound). The authors emphasize that GLP-1 medications can lead to substantial weight loss, ranging from 15% to 21%. Yet, diet and lifestyle factors remain critically important for optimal results.

“Many patients lose muscle mass (in addition to fat mass) and have GI symptoms that lead to stopping medication,” said senior author JoAnn E. Manson, MD, DrPH, chief of the Division of Preventive Medicine at Brigham and Women’s Hospital, a founding member of the Mass General Brigham health care system. “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.”

The authors offer strategies for clinicians to help patients maintain healthy nutrition and physical activity habits, including ensuring adequate hydration, protein intake, and exercise habits that include muscle strengthening. For physical activity, they suggest helping patients gradually increase movement, resistance training and aerobic exercise.

They also propose recommendations to address the challenge of maintaining weight loss and managing side effects like nausea, constipation, and fatigue.

“Although GLP-1 RAs 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.”