Obesity

Healthy Eating

What is obesity?

Body mass index (BMI) is a calculation that takes a person’s weight and height into account to measure body size.

Obesity is associated with a higher risk for serious diseases, such as type 2 diabetes, heart disease, and cancer.

What causes obesity?

Common specific causes of obesity include:

genetics, which can affect how your body processes food into energy and how fat is stored
growing older, which can lead to less muscle mass and a slower metabolic rate, making it easier to gain weight
not sleeping enough, which can lead to hormonal changes that make you feel hungrier and crave certain high-calorie foods
pregnancy, as weight gained during pregnancy may be difficult to lose and might eventually lead to obesity

Certain health conditions can also lead to weight gain, which may lead to obesity. These include:

polycystic ovary syndrome (PCOS), a condition that causes an imbalance of female reproductive hormones
Prader-Willi syndrome, a rare condition present at birth that causes excessive hunger
Cushing syndrome, a condition caused by having high cortisol levels (the stress hormone) in your system
hypothyroidism (underactive thyroid), a condition in which the thyroid gland doesn’t produce enough of certain important hormones
osteoarthritis (OA) and other conditions that cause pain that may lead to reduced activity

Who is at risk for obesity?

A complex mix of factors can increase a person’s risk for obesity.

Genetics

Some people have genes that make it difficult for them to lose weight.

Environment and community

Your environment at home, at school, and in your community can all influence how and what you eat, and how active you are.

You may be at a higher risk for obesity if you:

live in a neighborhood with limited healthy food options or with many high-calorie food options, like fast-food restaurants
haven’t yet learned to cook healthy meals
don’t think you can afford healthier foods
haven’t found a good place to play, walk, or exercise in your neighborhood

Psychological and other factors

Depression can sometimes lead to weight gain, as some people may turn to food for emotional comfort. Certain antidepressants can also increase the risk of weight gain.

Quitting smoking is always a good thing, but quitting may lead to weight gain too. In some people, it may lead to excessive weight gain. For that reason, it’s important to focus on diet and exercise while you’re quitting, at least after the initial withdrawal period.

Medications, such as steroids or birth control pills, can also raise your risk for weight gain.