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.

Behavior

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 of moderate intensity activity or 75 minutes of vigorous intensity activity, or a combination of both, along with 2 days of strength training per 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.

Community Environment

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 the many community environmental factors that have contributed to the obesity epidemic, as well as several community initiatives taking place to prevent and reduce obesity.

Learn about community strategies to make it easier to be physically active.

See strategies to prevent obesity and school health guidelines.

Genetics

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.

Other Factors: Diseases and Drugs

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

Health Consequences

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
• Stroke
• 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 disorders^8,9
• 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 iconexternal 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. In 2007-2008, 5.7 million men and 16.5 million women who were eligible for military service exceeded the Army’s enlistment standards for weight and body fat.¹⁷ The assessment was performed of the percentage of the US military-age population that exceeds the US Army’s current active duty enlistment standards for weight-for-height and percent body fat, using data from the National Health and Nutrition Examination Surveys.