Obesity, a major risk factor for many chronic diseases, has reached epidemic proportions globally. The effects of obesity on health are equivalent to 20 years aging. They include increased risk of cardiovascular disease, diabetes, cancer, rheumatoid arthritis, sleep apnea, gallbladder and liver disease. Overweight and obesity are both labels for ranges of weight that are greater than what is generally considered healthy for a given height. The terms also identify ranges of weight that have been shown to increase the likelihood of certain diseases and other health problems.
For adults, overweight and obesity ranges are determined by using weight and height to calculate a number called the “body mass index” (BMI). BMI is used because, for most people, it correlates with their amount of body fat. 

An adult who has a BMI between 25 and 29.9 is considered overweight.
An adult who has a BMI of 30 or higher is considered obese