GLP-1 medications have reshaped the treatment landscape for type 2 diabetes, lowering blood sugar and helping many patients lose weight. But a large new study suggests the drugs do not replace the basics of healthy living. Instead, they appear to work best alongside them.
In research published in The Lancet Diabetes & Endocrinology, investigators from Harvard T.H. Chan School of Public Health and the Department of Veterans Affairs examined data from more than 98,000 adults living with type 2 diabetes who had no prior cardiovascular disease. Participants were followed between 2011 and 2023 as part of the Million Veteran Program.
The researchers looked at two main factors: use of GLP-1 receptor agonists and adherence to eight healthy lifestyle habits. Those habits included a healthy diet, regular physical activity, not smoking, restful sleep, minimal alcohol intake, stress management, social connection and no opioid use disorder.
Over the follow-up period, participants who both used a GLP-1 medication and adhered to six to eight healthy habits had a 43% lower relative risk of experiencing a major adverse cardiovascular event, such as heart attack, stroke or cardiovascular death, compared with those who did not use a GLP-1 and adhered to three or fewer healthy habits.
Each factor also showed independent benefits. Participants who used a GLP-1 medication had a 16% lower relative risk of a cardiovascular event compared with non-users. Those who adhered to all eight healthy habits had a 60% lower relative risk compared with those who adhered to one or none.
“Our findings underscore that, even in the era of highly effective GLP-1 pharmacotherapy, lifestyle habits remain central to diabetes management and cardiovascular risk reduction and can substantially amplify the benefits of modern medications,” said senior author Frank Hu, Fredrick J. Stare Professor of Nutrition and Epidemiology and chair of the Department of Nutrition at Harvard Chan.
The study was observational, meaning it cannot prove that GLP-1 drugs or lifestyle habits directly caused the reduction in risk. While researchers adjusted for many demographic and health factors, residual confounding remains possible. In addition, most participants were white male veterans, which may limit generalizability to broader populations.
Still, the findings reinforce a consistent theme in cardiovascular prevention: medications and lifestyle strategies are complementary, not competing. GLP-1 drugs may reduce risk, but foundational habits such as diet quality, movement, sleep and smoking cessation remain powerful drivers of long-term heart health.
For patients and clinicians, the message is not either-or. Modern diabetes medications can offer meaningful protection. But the strongest cardiovascular benefits appear when those therapies are layered on top of healthy daily behaviors.
The study was based on data from the Veterans Affairs Million Veteran Program and supported by the U.S. Department of Veterans Affairs. One co-author reported receiving research funding or consulting fees from several pharmaceutical companies that manufacture diabetes medications.