Look AHEAD trial: 25 years of lifestyle change lessons

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The Look AHEAD trial: what 25 years of lifestyle change taught us about type 2 diabetes and obesity

By Dr. Asnat Raziel, bariatric surgeon specializing in obesity treatment, metabolic health and healthy longevity; Director of the Multidisciplinary Center for Obesity Treatment, Assia Medical, Assuta Ramat HaChayal, Tel Aviv

The Look AHEAD trial: lifestyle change put to the test of time

The Look AHEAD trial is one of the largest and longest studies in diabetes and obesity. Its name stands for Action for Health in Diabetes. It asked a seemingly simple question: does intensive lifestyle change reduce heart disease in people with type 2 diabetes? Now, after 25 years of follow-up, the researchers have published a retrospective review in the journal Diabetes Care. The picture it paints is sobering, but also encouraging.

The trial got under way in the early 2000s. Since then, obesity treatment has changed from top to bottom. Today, we also have very effective drugs for diabetes and obesity. That is exactly why it matters to understand what lifestyle alone can deliver, and what it cannot.

Everyday eating habits matter at every age. I discuss this in my piece on Trump’s diet and three practical lessons.

What did the Look AHEAD trial involve?

The trial enrolled 5,145 women and men aged 45 to 76. All of them had type 2 diabetes along with obesity or overweight. The researchers randomly assigned them to two groups at 16 centers in the United States.

The intensive lifestyle intervention group (ILI)

This group received close, structured support. The program included a tailored diet with a clear weight loss target. In addition, participants were given a goal of 175 minutes of physical activity a week. They also received individual and group behavioral support, along with medical follow-up over many years.

The control group: diabetes support and education (DSE)

This group attended a few group education sessions each year. The sessions covered nutrition, physical activity and social support. However, this group had no required weight loss target and no intensive program.

Results from the first year

Clear differences emerged within the first year. According to the main results published in NEJM, the intervention group lost an average of 8.6% of their body weight. The control group, by contrast, lost only 0.7%.

In addition, the intervention group improved their physical fitness and their HbA1c, the average blood sugar over the previous three months. Blood pressure and most heart risk factors also improved, except for LDL cholesterol. At this point, it seemed the trial was on its way to clear-cut proof.

Keeping the weight off over the years

The big question was what would happen after the first year. The 8-year data paint an encouraging picture. In the intervention group, 50.3% of participants maintained a loss of at least 5% of their weight. In the control group, by comparison, the rate was 35.7%. Moreover, 26.9% of the intervention group maintained a loss of at least 10%, compared with 17.2% of the control group.

Clearly, this is no small achievement. As we know, keeping weight off after weight loss is the hardest challenge in treatment. The researchers found that those who kept the weight off continued to practice regular weight control habits.

Diabetes remission: possible, but not for everyone

One of the key findings is that remission of type 2 diabetes is possible. Remission means normal or near-normal blood sugar levels without medication. In an analysis published in JAMA, 11.5% of the intervention group reached partial or complete remission in the first year. By comparison, the rate in the control group was 2.0%. After 4 years, the rate in the intervention group fell to 7.3%.

Even so, temporary remission had value. In a long-term follow-up published in 2024, participants who reached remission at any point had a 33% lower rate of chronic kidney disease. They also had a 40% lower rate of cardiovascular disease. Notably, the greatest benefit appeared in those whose remission lasted a long time. Keep in mind that this is a statistical association, not proof of cause and effect.

The Look AHEAD trial and the heart: a surprising result

Here comes the finding that disappointed many. Despite the improvements in weight, blood sugar and risk factors, the trial did not show a significant drop in heart attacks and strokes. A serious cardiovascular event occurred in 403 participants in the intervention group and in 418 in the control group. However, this difference is not statistically significant. As a result, the researchers stopped the active intervention phase earlier than planned, after a median follow-up of 9.6 years.

Above all, this finding teaches an important truth. Improvement in intermediate measures does not always lead to less disease. Also, the weight gap between the groups narrowed over the years, and by the end of the trial it stood at 6.0% vs. 3.5%. It is interesting to compare this with the SELECT trial, in which a GLP-1 drug reduced heart events in people with obesity and heart disease.

Quality of life, mobility and mood

Beyond the hard outcomes, the trial showed benefits that matter a great deal to patients. In a study on mobility, the intervention cut the risk of losing mobility after 4 years by 48%. In other words, participants were better able to keep walking and functioning independently.

The intervention also lowered the risk of depression symptoms by 15%, according to an analysis of mood and quality of life. Participants also reported good physical function over the first 8 years. On the other hand, there was no difference between the groups in the use of antidepressants.

The Look AHEAD trial 25 years on: a geroscience perspective

Meanwhile, follow-up of the participants continues today. In the 25-year review, the researchers look at the trial through the lens of geroscience, the field that studies the biology of aging. In their view, type 2 diabetes and obesity speed up biological aging. That makes lifestyle change a central part of treatment, with the aim of slowing that process. This idea connects directly to healthy aging.

In addition, a mortality analysis presented at the end of 2025 looked at 23 years of follow-up. Overall, all-cause mortality was 11% lower in the intervention group. However, this is a conference abstract, not a full paper. The researchers themselves noted that the difference came mainly from a subgroup of participants of Hispanic origin.

What the Look AHEAD trial teaches us today

The trial offers several key lessons. First, lifestyle change works even when diabetes is already present. Second, moderate, sustained weight loss improves health, mobility and quality of life. Third, not every metabolic improvement leads right away to fewer heart events. Finally, treatment for obesity and diabetes must be multidisciplinary, personalized and ongoing.

In the era of new drugs, the Look AHEAD trial reminds us of a simple principle. Lifestyle is not an alternative to medication or surgery. Instead, it is the foundation that strengthens every other tool. If you want to dig deeper, read about obesity and type 2 diabetes and about 21 years of follow-up in prediabetes.

The information in this article is general and does not replace personal medical advice.