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Summary
Obesity means having too much body fat. It is different from being overweight, which means weighing too much. The weight may come from muscle, bone, fat, and/or body water. Both terms mean that a person's weight is greater than what's considered healthy for his or her height.
Obesity happens over time when you eat more calories than you use. The balance between calories-in and calories-out differs for each person. Factors that might affect your weight include your genetic makeup, overeating, eating high-fat foods, and not being physically active.
Obesity increases your risk of diabetes, heart disease, stroke, arthritis, and some cancers. If you have obesity, losing even 5 to 10% of your weight can delay or prevent some of these diseases. For example, that means losing 10 to 20 pounds if you weigh 200 pounds.
NIH: National Institute of Diabetes and Digestive and Kidney Diseases
Diagnosis and Tests
- Assessing Your Weight and Health Risk (National Heart, Lung, and Blood Institute)
- Body Mass Index Table (National Heart, Lung, and Blood Institute)
- Obesity Screening (National Library of Medicine) Also in Spanish
Prevention and Risk Factors
- Aim For a Healthy Weight (National Heart, Lung, and Blood Institute)
- Balance Food and Activity (National Heart, Lung, and Blood Institute) Also in Spanish
Learn More
- Staying Active at Any Size (National Institute of Diabetes and Digestive and Kidney Diseases) Also in Spanish
Treatments and Therapies
- Weight Control: MedlinePlus Health Topic (National Library of Medicine) Also in Spanish
- Weight Loss Surgery: MedlinePlus Health Topic (National Library of Medicine) Also in Spanish
Related Issues
- Disability and Obesity (Centers for Disease Control and Prevention) Also in Spanish
- Obesity (American Society of Anesthesiologists)
- Obesity (Endocrine Society)
- Obesity and Cancer (National Cancer Institute) Also in Spanish
- Obesity and Your Digestive Health (American College of Gastroenterology) - PDF
Specifics
- Health Risks of Overweight and Obesity (National Institute of Diabetes and Digestive and Kidney Diseases) Also in Spanish
- Obesity (American Psychological Association) Also in Spanish
- Obesity Hypoventilation Syndrome (National Heart, Lung, and Blood Institute)
- Understanding Adult Overweight and Obesity (National Institute of Diabetes and Digestive and Kidney Diseases) Also in Spanish
- Weight Management and Healthy Living Tips (National Institute of Diabetes and Digestive and Kidney Diseases)
Genetics
- Congenital leptin deficiency: MedlinePlus Genetics (National Library of Medicine)
- Leptin receptor deficiency: MedlinePlus Genetics (National Library of Medicine)
- Proopiomelanocortin deficiency: MedlinePlus Genetics (National Library of Medicine)
Health Check Tools
- Calculate Your Body Mass Index (National Heart, Lung, and Blood Institute) Also in Spanish
Test Your Knowledge
- Test Your Weight Loss Knowledge (Medical Encyclopedia) Also in Spanish
- Weight Loss Myths & Facts Quiz (Medical Encyclopedia) Also in Spanish
Statistics and Research
- Diabetes Interactive Atlas (Centers for Disease Control and Prevention)
- FastStats: Obesity and Overweight (National Center for Health Statistics)
- Obesity and Cancer (Centers for Disease Control and Prevention) Also in Spanish
- Overweight and Obesity Statistics (National Institute of Diabetes and Digestive and Kidney Diseases)
Clinical Trials
- ClinicalTrials.gov: Obesity (National Institutes of Health)
Journal Articles References and abstracts from MEDLINE/PubMed (National Library of Medicine)
- Article: Prolonged Water-Only Fasting Followed by a Whole-Plant-Food Diet Is a Potential...
- Article: Combined high-intensity interval and resistance training improves cardiorespiratory fitness more than...
- Article: The Impact of Telemonitoring and Telehealth Coaching on General Nutrition Knowledge...
- Obesity -- see more articles
Find an Expert
- Find a Nutrition Expert (Academy of Nutrition and Dietetics)
- Find an Obesity Medicine Clinician (Obesity Medicine Association)
- National Heart, Lung, and Blood Institute
- National Institute of Diabetes and Digestive and Kidney Diseases
Children
- Obesity in Children: MedlinePlus Health Topic (National Library of Medicine) Also in Spanish
Teenagers
- Dealing With Feelings When You're Overweight (For Teens) (Nemours Foundation) Also in Spanish
Men
- Belly Fat in Men: Why Weight Loss Matters (Mayo Foundation for Medical Education and Research) Also in Spanish
Women
- Belly Fat in Women: Taking -- and Keeping -- It off (Mayo Foundation for Medical Education and Research) Also in Spanish
- Pregnancy and Obesity: Know the Risks (Mayo Foundation for Medical Education and Research)
Patient Handouts
- Body mass index (Medical Encyclopedia) Also in Spanish
- Health risks of obesity (Medical Encyclopedia) Also in Spanish
- Obesity (Medical Encyclopedia) Also in Spanish
- Obesity hypoventilation syndrome (OHS) (Medical Encyclopedia) Also in Spanish