Obesity and Overweight

Weight that is higher than what is considered healthy, based on a person’s height, is called “overweight” or “obesity.” Obesity is a chronic disease.

The most common way to determine if a person has overweight or obesity is to calculate body mass index (BMI), an estimate of body fat based on comparing a person’s weight to their height.

To lose weight, a person usually needs to reduce calories and increase physical activity. If lifestyle changes are not enough, medicines and weight-loss surgery may also be options.

Several factors can play a role in weight gain and retention, including diet, lack of exercise, factors in a person’s environment, and genetics. 

NICHD conducts and supports research on obesity and overweight and on many associated disorders.

NICHD conducts and supports a variety of clinical research projects related to obesity and overweight.

Find answers to other common questions about obesity and overweight, such as associated disorders and whether obesity and overweight can affect pregnancy and fertility.

Links to websites of groups that study or provide information about obesity and overweight.