Prediabetes now affects roughly one in three American adults, according to the U.S. Centers for Disease Control and Prevention (CDC), and more than 80% of them don’t know they have it. Left unaddressed, it commonly progresses to type 2 diabetes and raises the risk of heart disease, kidney disease, and cognitive decline. A long-running NIH-supported clinical trial has offered a clearer answer to a question millions of people quietly ask their doctors: is it better to try lifestyle change first, or start medication?
The latest follow-up findings from the Diabetes Prevention Program (DPP) suggest that a structured lifestyle intervention outperforms metformin, the most commonly prescribed prediabetes medication, in reducing the risk of multiple chronic conditions over the long term. The results, updated in 2026, extend more than two decades of research on one of the largest diabetes prevention studies ever conducted.
What the NIH Diabetes Prevention Program Actually Studied
The original DPP, funded by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), enrolled more than 3,000 adults with prediabetes in the late 1990s. Participants were randomly assigned to one of three groups: an intensive lifestyle program, metformin (a well-tolerated generic diabetes drug), or a placebo.
The intensive lifestyle group aimed for two concrete targets: about 7% body weight loss and at least 150 minutes per week of moderate physical activity, such as brisk walking. Participants received structured coaching on nutrition, portion sizes, and behavior change during the initial phase.
The first major results, published in the New England Journal of Medicine in 2002, showed the lifestyle group reduced their risk of developing type 2 diabetes by 58%, compared with a 31% reduction in the metformin group. Since then, researchers have followed the same participants through the Diabetes Prevention Program Outcomes Study (DPPOS) to see how those early benefits held up over decades.
Why Lifestyle Change Kept Winning Over Time
Long-term follow-up analyses have consistently shown that early lifestyle intervention leaves a durable footprint on health, even after the structured coaching ends. The most recent NIH update indicates that lifestyle participants had a lower cumulative risk of developing multiple chronic conditions, not just diabetes, compared with those originally assigned to metformin.
Researchers point to several likely reasons:
- Metabolic memory: Early weight loss and improved insulin sensitivity appear to shift the body’s long-term metabolic trajectory, even if some weight is regained.
- Broader risk reduction: Regular activity and a whole-foods diet influence blood pressure, cholesterol, inflammation, and sleep quality, effects that a single medication does not fully replicate.
- Behavior spillover: Participants who built consistent movement and cooking habits often maintained them, compounding benefits over years.
Metformin still lowered diabetes risk significantly and remained particularly effective in adults under 60 and those with a higher body mass index. But across the broader set of chronic outcomes, the lifestyle arm pulled ahead.
What “Lifestyle Intervention” Really Looks Like
One of the most useful contributions of the DPP is a clear picture of what actually works. The intervention was not a fad diet or extreme workout program. It was modest, sustained change.
The Weight Loss Target
A 7% weight loss for a 200-pound adult is about 14 pounds. Research suggests this modest amount is enough to meaningfully improve insulin sensitivity, blood pressure, and lipid profiles, without the physiological pushback that steeper weight loss often triggers.
The Activity Target
Roughly 150 minutes per week of moderate activity works out to about 30 minutes, five days a week. Brisk walking counts. So does cycling, swimming, dancing, or gardening at a pace that raises the heart rate.
The Eating Pattern
The DPP did not prescribe a single diet. Instead, it emphasized reduced calorie intake, lower saturated fat, and higher fiber, principles compatible with the Mediterranean pattern, plant-forward eating, or a balanced omnivorous plate. National guidelines from the American Diabetes Association similarly emphasize non-starchy vegetables, whole grains, legumes, lean proteins, and healthy fats.
Where Metformin Still Has an Important Role
The findings do not suggest people should avoid metformin. It remains one of the safest, most affordable, and best-studied medications in modern medicine. Guidelines from the American Diabetes Association continue to recommend considering metformin for prediabetes in adults under 60, those with a body mass index of 35 or higher, and women with a history of gestational diabetes.
For many patients, the practical answer is not lifestyle or medication, but a combination. Metformin may help stabilize blood sugar while a person builds sustainable habits, and some people continue both indefinitely under medical guidance.
Practical Takeaways From the Research
For adults with prediabetes, or those with risk factors such as family history, higher body weight, gestational diabetes, or polycystic ovary syndrome, the DPP evidence points to several evidence-based priorities:
- Know your numbers. A fasting glucose test, HbA1c, or oral glucose tolerance test can identify prediabetes early. The CDC estimates most cases are undiagnosed.
- Aim for modest, sustained weight loss if a healthcare provider determines it’s appropriate, rather than aggressive short-term diets.
- Prioritize consistent movement across the week rather than occasional intense workouts.
- Build a fiber-rich, minimally processed eating pattern that fits your culture, budget, and preferences.
- Ask about the National DPP. The CDC-recognized National Diabetes Prevention Program offers year-long structured coaching, often covered by insurance and Medicare.
The Bigger Picture on Preventive Medicine
The DPP has become a reference point in preventive medicine in part because it studied real-world behavior change over decades, not just short-term outcomes. Its long-term data reinforces a broader theme emerging across cardiovascular, cognitive, and cancer research: early, modest, sustained lifestyle changes tend to compound.
That does not diminish the value of medication when it’s needed. It does suggest that when prediabetes is caught early, the most powerful tools available are often the ones patients can start using this week: a walk, a shift toward whole foods, and consistent sleep.
Disclosure: This content is for informational purposes only and is not medical advice. Always consult a qualified healthcare provider before making changes to your health regimen.