GLP-1 Weight-Loss Drugs Trim Pounds But Also Trim Activity

A study presented at ENDO 2026 analyzed Fitbit data from NIH All of Us and found that adults with obesity who started GLP-1 medications (semaglutide or tirzepatide) lost weight but became less physically active. Average daily steps dropped from 5,047 to 4,487 and moderate-to-vigorous physical activity fell from 28 to 22 minutes per day, with the largest decreases in men and those reporting joint/muscle pain. Age, heart failure, and prior stroke did not change the trend. The researchers stress that exercise should accompany GLP-1 therapy to protect muscle and long-term health, marking the first large wearable-data study of activity in users of these drugs.