Researchers from the German Institute of Nutrition and the Harvard TH Chan School of Public Health tracked the health of more than 90,000 women over 30 years in a study looking at the risk of having a heart attack or stroke. It found that women who were a normal weight and metabolically healthy had the lowest risk, whereas those who were obese and metabolically healthy had a 39 per cent increased risk. The research also suggests high blood pressure and diabetes are most strongly associated with heart attack or stroke.