People who are too thin have a much higher chance of dying early—even more than those who are obese—suggesting being underweight is just as dangerous as being very overweight.

Being underweight, overweight, or obese at the start of the study didn't significantly change the risk of death compared to having a normal weight in older adults.

People with heart disease who are obese (BMI 30 or higher) have a 23% higher chance of dying from any cause compared to those who are overweight (BMI 25-30).

Older adults who lose more than 5% of their body weight are more likely to die within the study period compared to those whose weight stays stable.

If you're middle-aged and carry extra weight (even if you're not obese), you're 34% more likely to have a heart attack or stroke over the next 17 years — even if you don’t have diabetes, high blood pressure, or kidney disease. This suggests your extra fat might be harming your heart in ways we don’t fully understand yet.

Being severely obese doesn’t automatically mean you’re at higher risk of dying—what matters more is whether you carry fat around your middle.