Adult Obesity Causes & Consequences
Obesity is a complex health issue resulting from a combination of causes and individual factors such as behavior and genetics. Behaviors can include physical activity, inactivity, dietary patterns, medication use, and other exposures. Additional contributing factors include the food and physical activity environment, education and skills, and food marketing and promotion.
Obesity is serious because it is associated with poorer mental health outcomes and reduced quality of life. Obesity is also associated with the leading causes of death in the United States and worldwide, including diabetes, heart disease, stroke, and some types of cancer.
Healthy behaviors include regular physical activity and healthy eating. Balancing the number of calories consumed from foods and beverages with the number of calories the body uses for activity plays a role in preventing excess weight gain.1,2 The Physical Activity Guidelines for Americansexternal icon recommends adults do at least 150 minutes a week of moderate intensity activity such as brisk walking. In addition, adults need to do activities that strengthen muscles at least 2 days a week.
A healthy diet pattern follows the Dietary Guidelines for Americansexternal icon which emphasizes eating whole grains, fruits, vegetables, lean protein, low-fat and fat-free dairy products, and drinking water.
A pattern of healthy eating and regular physical activity is also important for long-term health benefits and prevention of chronic diseases such as type 2 diabetes and heart disease.
For more, see Healthy Weight – Finding a Balance.
People and families may make decisions based on their environment or community. For example, a person may not walk or bike to the store or to work because of a lack of sidewalks or safe bike trails. Community, home, childcare, school, health care, and workplace settings can all influence daily behaviors. Therefore, it is important to create environments that make it easier to engage in physical activity and eat healthy foods.
Watch The Obesity Epidemic external iconto learn about factors that contribute to the obesity epidemic, as well as several community initiatives to prevent and reduce obesity.
Learn about community strategies to make it easier to be physically active.
Do Genes Have a Role in Obesity?
Genetic changes in human populations occur too slowly to be responsible for the obesity epidemic. Nevertheless, how people respond to an environment that promotes physical inactivity and intake of high-calorie foods suggests that genes do play a role in developing obesity.
How Could Genes Influence Obesity?
Genes give the body instructions for responding to changes in its environment. Variants in several genes may contribute to obesity by increasing hunger and food intake.
Rarely, a clear pattern of inherited obesity within a family is caused by a specific variant of a single gene (monogenic obesity). Most obesity, however, probably results from complex interactions among multiple genes and environmental factors that remain poorly understood (multifactorial obesity).3,4
What about Family History?
Health care practitioners routinely collect family health history to help identify people at high risk of obesity-related diseases such as diabetes, cardiovascular diseases, and some forms of cancer. Family health history reflects the effects of shared genetics and environment among close relatives. Families cannot change their genes, but they can encourage healthy eating habits and physical activity. Those changes can improve the health of family members—and improve the health history of the next generation.3,4
Learn more about obesity and genomics.
Some illnesses may lead to obesity or weight gain. These may include Cushing’s disease, and polycystic ovary syndrome. Drugs such as steroids and some antidepressants may also cause weight gain. Research continues on the role of other factors in energy balance and weight gain such as chemical exposures and the role of the microbiome.
A health care provider can help you learn more about your health habits and history to identify whether behaviors, illnesses, medications, and/or psychological factors are contributing to weight gain or making weight loss hard.
Consequences of Obesity
People who have obesity, compared to those with a healthy weight, are at increased risk for many serious diseases and health conditions, including the following:5,6,7
- All-causes of death (mortality)
- High blood pressure (hypertension)
- High LDL cholesterol, low HDL cholesterol, or high levels of triglycerides (Dyslipidemia)
- Type 2 diabetes
- Coronary heart disease
- Gallbladder disease
- Osteoarthritis (a breakdown of cartilage and bone within a joint)
- Sleep apnea and breathing problems
- Many types of cancers external icon
- Low quality of life
- Mental illness such as clinical depression, anxiety, and other mental disorders8,9
- Body pain and difficulty with physical functioning10
For more information, visit Health Effects of Overweight and Obesity and Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults. pdf icon[PDF-1.24MB]external icon
Economic and Societal Consequences
Obesity and its associated health problems have a significant economic impact on the US health care system,11 including direct and indirect costs.12,13 Direct medical costs may include preventive, diagnostic, and treatment services. Indirect costs relate to sickness and death and include lost productivity. Productivity measures include employees being absent from work for obesity-related health reasons, decreased productivity while at work, and premature death and disability.14
National Estimated Costs of Obesity
Obesity-related medical care costs in the United States, in 2008 dollars, were an estimated $147 billion.15 Annual nationwide productivity costs of obesity-related absenteeism range between $3.38 billion ($79 per obese individual) and $6.38 billion ($132 per individual with obesity).16
In addition, obesity has implications for armed forces recruitment. Nationwide, 71% of people between the ages of 17 and 24 do not qualify for military service; obesity disqualifies 31% of them from serving if they so choose.17
3Bouchard C. Defining the genetic architecture of the predisposition to obesity: a challenging but not insurmountable taskexternal icon. Am J Clin Nutr 2010; 91:5-6.
4Choquet H, Meyre D. Genetics of obesity: what have we learned?external icon Curr Genomics. 2011;12:169-79.
7Bhaskaran K, Douglas I, Forbes H, dos-Santos-Silva I, Leon DA, Smeeth L. Body-mass
index and risk of 22 specific cancers: a population-based cohort study of 5•24 million UK adults. Lancet. 2014 Aug 30;384(9945):755-65. doi: 10.1016/S0140-6736(14)60892-8. Epub 2014 Aug 13.
8Kasen, Stephanie, et al. “Obesity and psychopathology in women: a three decade prospective study.” International Journal of Obesity 32.3 (2008): 558-566.
9Luppino, Floriana S., et al. “Overweight, obesity, and depression: a systematic review and meta-analysis of longitudinal studies.” Archives of general psychiatry 67.3 (2010): 220-229.
10Roberts, Robert E., et al. “Prospective association between obesity and depression: evidence from the Alameda County Study.” International journal of obesity 27.4 (2003): 514-521.
11U.S. Department of Health and Human Services. The Surgeon General’s call to action to prevent and decrease overweight and obesity. [Rockville, MD]: U.S. Department of Health and Human Services, Public Health Service, Office of the Surgeon General; . Available from: US GPO, Washington.
12Wolf AM, Colditz GA. Current estimates of the economic cost of obesity in the United States. Obesity Research.1998;6(2):97–106.
13Wolf, A. What is the economic case for treating obesity? Obesity Research. 1998 Apr;6 Suppl 1:2S-7S.
14Hammond RA, Levine R. The economic impact of obesity in the United States. Diabetes, metabolic syndrome and obesity : targets and therapy. 2010;3:285-295. doi:10.2147/DMSOTT.S7384.
15Finkelstein EA1, Trogdon JG, Cohen JW, Dietz W. Annual medical spending attributable to obesity: payer-and service-specific estimates. Health Aff (Millwood). 2009 Sep-Oct;28(5):w822-31. doi: 10.1377/hlthaff.28.5.w822.
16Trogdon JG, Finkelstein EA, Hylands T, Dellea PS, Kamal-Bahl. Indirect costs of obesity: a review of the current literature. Obes Rev.2008;9(5):489–500.
17Maxey H, Bishop S, Goodman B, Browning D. Breaking Point: Child malnutrition imperils America’s national security. Mission: Readiness Council for a Strong America; 2020.