Overweight refers to an excess amount of body weight that includes muscle, bone, fat, and water. It is defined as having a body mass index (BMI) of 25 or higher. BMI is a measure of body fat based on height and weight, and it is used to classify individuals as underweight, normal weight, overweight, or obese. Being overweight is not necessarily a health problem in and of itself, but it can increase the risk of several health problems, including cardiovascular disease, type 2 diabetes, certain cancers, musculoskeletal problems, sleep apnea, and mental health problems. Losing excess weight can help reduce the risk of these and other health problems and improve overall health.