Losing weight with diet and exercise doesn’t always help the heart in people with type 2 diabetes—sometimes it helps a lot, sometimes it doesn’t help at all, and sometimes it might even make things worse.

For some people with type 2 diabetes who are overweight, losing weight through diet and exercise can lower their chance of having a heart attack or stroke—but for others, it might actually increase that risk.

For people with type 2 diabetes, factors like age, weight, blood sugar levels, and past heart problems can tell us whether losing weight through diet and exercise will help or hurt their heart health.

Making lasting changes to how you eat and move can help stop prediabetes from turning into full-blown diabetes—but in real life, most people struggle to stick with these changes, so they don’t work as well as they do in fancy research studies.

If you’re overweight (BMI 23 or higher), having type 2 diabetes explains about a quarter of why you’re more likely to have heart problems — meaning diabetes is a big reason why extra weight hurts your heart.

When obese adults take medicines to lose weight, they’re much less likely to die from heart problems — about half as likely — probably because losing weight helps their blood pressure, sugar, and other heart-related numbers get better.