Factors Affecting Weight & Health

Many factors can affect your weight, including

Lifestyle habits

Lifestyle habits—including the foods and beverages you consume and how active you are in your daily life—can also affect your weight. If you take in more calories from food or beverages than you use during physical activity and through daily living, such as doing housework or walking to the store, your body may store some of these extra calories as fat. Lifestyle habits that may lead to weight gain include

  • eating or drinking a lot of foods and beverages that are high in calories, sugar, and fat 
  • drinking a lot of beverages that are high in added sugars 
  • spending a lot of time sitting or lying down

Over time, if you continue to take in more calories than you use, you will likely gain weight.

Where you live, work, play, and worship

Where you live, work, play, and worship can also make a difference. It may be easier for you to make healthier lifestyle choices if

  • you live near a grocery store that offers healthy affordable foods, including fruits and vegetables
  • your workplace has a kitchen where you can store and prepare healthy meals you bring from home
  • your job doesn’t require you to spend a lot of time sitting down
  • your neighborhood has safe places to walk or do other types of physical activity
  • your place of worship includes healthy food options at special events

How much sleep you get

Woman sleeping in her bed.Adults ages 18 to 64 should get 7 to 9 hours of sleep a night.

Not getting enough sleep is also linked to weight gain. Experts recommend that adults ages 18 to 64 get 7 to 9 hours of sleep a night. Adults ages 65 and older should get 7 to 8 hours of sleep a night.4

Not getting enough sleep may make you feel hungrier, consume more calories, and be more likely to choose unhealthy foods and beverages instead of healthier options.5 Getting enough sleep may help prevent these problems and increase overall well-being.


Some medicines can affect your energy balance by making you hungry or making your body burn fewer calories. Medicines that may contribute to weight gain include6

Health problems

Some health problems may also lead to obesity or weight gain. Examples include6

Some eating disorders, such as binge-eating disorder and bulimia nervosa, may also lead to obesity or weight gain. Both disorders involve eating a large amount of food while feeling a loss of control. In bulimia, people try to prevent weight gain in unhealthy ways, such as by vomiting or using laxatives.

Family history and genes

Your chances of having overweight or obesity are greater if one or both of your parents have overweight or obesity.7 Children whose mothers had obesity during pregnancy are also more likely to have obesity themselves.8 Children and adolescents who have obesity are more likely to have obesity as adults.

Your genes may also affect both the amount of fat you store in your body and where on your body you carry the extra fat. Genes may also play a role in your appetite and how physically active you are.


Last Reviewed May 2023
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This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. NIDDK translates and disseminates research findings to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Content produced by NIDDK is carefully reviewed by NIDDK scientists and other experts.