Connect with others who've been there.Share stories. Learn. Join Mayo Clinic's
online community.

Free

E-newsletter

Subscribe to Housecall

Our weekly general interest
e-newsletter keeps you up to date on a wide variety of health topics.

Sign up now
View the Mayo Diabetes Diet Book

Risk factors

By Mayo Clinic staff

Obesity occurs when you eat and drink more calories than you burn through exercise and normal daily activities. Your body stores these extra calories as fat. Obesity usually results from a combination of causes and contributing factors, including:

  • Genetics. Your genes may affect the amount of body fat you store and where that fat is distributed. Genetics may also play a role in how efficiently your body converts food into energy and how your body burns calories during exercise. Even when someone has a genetic predisposition, environmental factors ultimately make you gain more weight.
  • Inactivity. If you're not very active, you don't burn as many calories. With a sedentary lifestyle, you can easily take in more calories every day than you burn off through exercise and normal daily activities.
  • Unhealthy diet and eating habits. Having a diet that's high in calories, eating fast food, skipping breakfast, consuming high-calorie drinks and eating oversized portions all contribute to weight gain.
  • Family lifestyle. Obesity tends to run in families. That's not just because of genetics. Family members tend to have similar eating, lifestyle and activity habits. If one or both of your parents are obese, your risk of being obese is increased.
  • Quitting smoking. Quitting smoking is often associated with weight gain. And for some, it can lead to a weight gain of as much as several pounds a week for several months, which can result in obesity. In the long run, however, quitting smoking is still a greater benefit to your health than continuing to smoke.
  • Pregnancy. During pregnancy a woman's weight necessarily increases. Some women find this weight difficult to lose after the baby is born. This weight gain may contribute to the development of obesity in women.
  • Lack of sleep. Not getting enough sleep at night can cause changes in hormones that increase your appetite. You may also crave foods high in calories and carbohydrates, which can contribute to weight gain.
  • Certain medications. Some medications can lead to weight gain if you don't compensate through diet or activity. These medications include some antidepressants, anti-seizure medications, diabetes medications, antipsychotic medications, steroids and beta blockers.
  • Age. Obesity can occur at any age, even in young children. But as you age, hormonal changes and a less active lifestyle increase your risk of obesity. In addition, the amount of muscle in your body tends to decrease with age. This lower muscle mass leads to a decrease in metabolism. These changes also reduce calorie needs and can make it harder to keep off excess weight. If you don't control what you eat as you age, you'll likely gain weight.
  • Social and economic issues. Certain social and economic issues may be linked to obesity. You may not have safe areas to exercise, you may not have been taught healthy ways of cooking, or you may not have money to buy healthier foods. In addition, the people you spend time with may influence your weight — you're more likely to become obese if you have obese friends or relatives.
  • Medical problems. Obesity can rarely be traced to a medical cause, such as Prader-Willi syndrome, Cushing's syndrome, polycystic ovary syndrome, and other diseases and conditions. Some medical problems, such as arthritis, can lead to decreased activity, which may result in weight gain. A low metabolism is unlikely to cause obesity, as is having low thyroid function.

Even if you have one or more of these risk factors, it doesn't mean that you're destined to become obese. You can counteract most risk factors through diet, physical activity and exercise, and behavior changes.

Complications Causes
References
  1. Defining overweight and obesity. Centers for Disease Control & Prevention. http://www.cdc.gov/obesity/defining.html. Accessed March 14, 2012.
  2. Bope ET, et al. Conn's Current Therapy. Philadelphia, Pa.: Saunders Elsevier; 2012. http://www.mdconsult.com/books/about.do?eid=4-u1.0-B978-1-4377-0986-5..C2009-0-38984-9--TOP&isbn=978-1-4377-0986-5&about=true&uniqId=236797353-5. Accessed March 14, 2012.
  3. Bray GA. Etiology and natural history of obesity. http://www.uptodate.com/index. Accessed March 14, 2012.
  4. Health care guideline: Prevention and management of obesity (mature adolescents and adults). Bloomington, Minn.: Institute for Clinical Systems Improvement. http://www.icsi.org/obesity/obesity_3398.html. Accessed Feb. 7, 2012.
  5. Understanding adult obesity. National Institute of Diabetes and Digestive and Kidney Diseases. http://www.win.niddk.nih.gov/publications/understanding.htm. Accessed March 15, 2012.
  6. Bray GA. Overview of therapy for obesity in adults. http://www.uptodate.com/index. Accessed March 14, 2012.
  7. The practical guide: Identification, evaluation, and treatment of overweight and obesity in adults. U.S. Department of Health and Human Services. http://www.nhlbi.nih.gov/guidelines/obesity/. Accessed March 15, 2012.
  8. Donnelly JE, et al. American College of Sports Medicine position stand: Appropriate physical activity intervention strategies for weight loss and prevention of weight regain for adults. Medicine & Science in Sports & Exercise. 2009;41:459.
  9. Sacks F, et al. Comparison of weight-loss diets with different compositions of fat, protein, and carbohydrates. New England Journal of Medicine. 2009;360:859.
  10. Andrews RA, et al. Surgical management of severe obesity. http://www.uptodate.com/index. Accessed March 14, 2012.
  11. Najm W, et al. Herbals used for diabetes, obesity, and metabolic syndrome. Primary Care. 2010;37:237.
  12. Cho SH, et al. Acupuncture for obesity: A systematic review and meta-analysis. International Journal of Obesity. 2009;33:183.
  13. Completed safety review: Xenical/Alli (Orlistat) and severe liver injury. U.S. Food and Drug Administration. http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm213038.htm. Accessed Feb. 16, 2011.
  14. Sarwer DB, et al. A review of the relationships between extreme obesity, quality of life, and sexual function. Obesity Surgery. 2012;22:668.
  15. Bray GA. Health hazards associated with obesity in adults. http://www.uptodate.com/index. Accessed March 14, 2012.
  16. FDA expands use of banding system for weight loss. U.S. Food and Drug Administration. http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm245617.htm. Accessed Feb. 7, 2012.
  17. Belviq (prescribing information). San Diego, Calif.: Arena Pharmaceuticals; 2012. http://invest.arenapharm.com. Accessed June 29, 2012.
  18. FDA approves Belviq to treat some overweight or obese adults. U.S. Food and Drug Administration. http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm309993.htm. Accessed July 23, 2012.
  19. FDA approves weight-management drug Qsymia. U.S. Food and Drug Administration. http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm312468.htm. Accessed July 18, 2012.
  20. Qsymia (prescribing information). Mountain View, Calif.: Vivus Inc.; 2012. http://www.vivus.com/products. Accessed July 18, 2012.
DS00314 Aug. 3, 2012

© 1998-2012 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. A single copy of these materials may be reprinted for noncommercial personal use only. "Mayo," "Mayo Clinic," "MayoClinic.com," "EmbodyHealth," "Enhance your life," and the triple-shield Mayo Clinic logo are trademarks of Mayo Foundation for Medical Education and Research.

  • Reprints
  • Print

  • Share on:

  • Email

Advertisement


Text Size: smallerlargerlarger