Obesity is defined as excessive body fat accumulation that presents a risk to health. It is a global issue, with over 650 million obese adults worldwide in 2016. Key causes include physical inactivity, overeating, genetics, and high calorie diets. Health risks include increased risk of heart disease, diabetes, cancers, respiratory issues and more. Treatment involves lifestyle changes like diet modification, increased physical activity, behavior therapy and sometimes medication or surgery. Managing obesity requires a comprehensive approach across several domains.