Depression can sometimes lead to weight gain, as people turn to food for emotional comfort. Certain antidepressants can also increase risk of weight gain.
According to the Centers for Disease Control and Prevention (CDC), it’s estimated that in 2015–2016, 93.3 million (
Obesity is defined as having a body mass index (BMI) of 30 or more. BMI is a calculation that takes a person’s weight and height into account. However, BMI does have some limitations.
According to the
Despite these limitations, BMI continues to be widely used as an indicator of excess weight.
Eating more calories than you burn in daily activity and exercise (on a long-term basis) causes obesity. Over time, these extra calories add up and cause you to gain weight.
Common specific causes of obesity include:
- eating a poor diet of foods high in fats and calories
- having a sedentary (inactive) lifestyle
- not sleeping enough, which can lead to hormonal changes that make you feel hungrier and crave certain high-calorie foods
- 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
- pregnancy (weight gained during pregnancy can be difficult to lose and may eventually lead to obesity)
Certain medical conditions may also lead to weight gain. These include:
- polycystic ovary syndrome (PCOS): a condition that causes an imbalance of female reproductive hormones
- Prader-Willi syndrome: a rare condition that an individual is born with which causes excessive hunger
- Cushing syndrome: a condition caused by having an excessive amount of the hormone cortisol in your system
- hypothyroidism (underactive thyroid): a condition in which the thyroid gland doesn’t produce enough of certain important hormones
- osteoarthritis (and other conditions that cause pain that may lead to inactivity)
A complex mix of genetic, environmental, and psychological factors can increase a person’s risk for obesity.
Some people possess genetic factors 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. Maybe you haven’t learned to cook healthy meals or don’t think you can afford healthier foods. If your neighborhood is unsafe, maybe you haven’t found a good place to play, walk, or run.
Psychological and other factors
It’s a good thing to quit smoking, but quitting can also lead to weight gain. For that reason, it’s important to focus on diet and exercise while you’re quitting.
Obesity is defined as having a BMI of 30 or more. Body mass index is a rough calculation of a person’s weight in relation to their height.
Other more accurate measures of body fat and body fat distribution include skinfold thickness, waist-to-hip comparisons, and screening tests such as ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) scans.
Your doctor may also order certain tests to help diagnose obesity as well as obesity-related health risks. These may include blood tests to examine cholesterol and glucose levels, liver function tests, diabetes screen, thyroid tests, and heart tests, such as an electrocardiogram.
A measurement of the fat around your waist is also a good predictor of risk for obesity-related diseases.
Obesity leads to much more than simple weight gain. Having a high ratio of body fat to muscle puts strain on your bones as well as your internal organs. It also increases inflammation in the body, which is thought to be a cause of cancer. Obesity is also a major cause of type 2 diabetes.
Obesity has been linked to a number of health complications, some of which are life-threatening:
- type 2 diabetes
- heart disease
- high blood pressure
- certain cancers (breast, colon, and endometrial)
- gallbladder disease
- fatty liver disease
- high cholesterol
- sleep apnea and other breathing problems