Rigorous scientific evidence linking overweight or obesity with increased risk for stroke is missing.
Overweight and obesity are important public health problems and are associated with many serious health conditions including stroke which is a leading cause of death and severe long-term disability. It appears logical that weight reduction in overweight or obese people should have positive health consequences lowering the number and consequences of strokes. Overweight is defined as a "body mass index" (BMI) between 25.0 and 29.9 kg/m2, if weight measured in kilogram is divided by height measured in meter, and obesity as a BMI equal or greater than 29.9 kg/m2.
Despite a thorough search of the available literature we were not able to identify any study of good quality investigating the relationship between weight reduction and the occurrence of strokes. If overweight or obese people want to reduce their risk profile by losing weight they need sound evidence for doing so since every intervention might have negative consequences as well, for example losing and regaining weight ("weight cycling") is associated with health hazards like cardiovascular diseases. There is an urgent need for adequate research (good randomised controlled clinical trials) hopefully providing better advice in the future.