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Summary
Do you know if your current weight is healthy? "Underweight", "normal", "overweight", and "obese" are all labels for ranges of weight. Obese and overweight mean that your weight is greater than it should be for your health. Underweight means that it is lower than it should be for your health. Your healthy body weight depends on your sex and height. For children, it also depends on your age.
A sudden, unexpected change in weight can be a sign of a medical problem. Causes for sudden weight loss can include:
- Thyroid problems
- Cancer
- Infectious diseases
- Digestive diseases
- Certain medicines
Sudden weight gain can be due to medicines, thyroid problems, heart failure, and kidney disease.
Good nutrition and exercise can help in losing weight. Eating extra calories within a well-balanced diet and treating any underlying medical problems can help to add weight.
- About Body Mass Index (BMI) (Centers for Disease Control and Prevention) Also in Spanish
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Assessing Your Weight and Health Risk
(National Heart, Lung, and Blood Institute)
Related Issues
- Antidepressants and Weight Gain: What Causes It? (Mayo Foundation for Medical Education and Research) Also in Spanish
- Beta Blockers: Do They Cause Weight Gain? (Mayo Foundation for Medical Education and Research) Also in Spanish
- Body Image and Mental Health (Department of Health and Human Services, Office on Women's Health) Also in Spanish
- Thyroid and Weight (American Thyroid Association) Also in Spanish
Specifics
- BMI Frequently Asked Questions (Centers for Disease Control and Prevention) Also in Spanish
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Health Risks of Overweight and Obesity
(National Institute of Diabetes and Digestive and Kidney Diseases)
Also in Spanish
- Tips for Maintaining Healthy Weight (Centers for Disease Control and Prevention)
- Unexplained Weight Loss (Mayo Foundation for Medical Education and Research) Also in Spanish
Health Check Tools
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Calculate Your Body Mass Index
(National Heart, Lung, and Blood Institute)
Also in Spanish
Statistics and Research
- FastStats: Obesity and Overweight (National Center for Health Statistics)
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Overweight and Obesity Statistics
(National Institute of Diabetes and Digestive and Kidney Diseases)
Clinical Trials
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ClinicalTrials.gov: Body Mass Index
(National Institutes of Health)
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ClinicalTrials.gov: Body Weight
(National Institutes of Health)
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ClinicalTrials.gov: Body Weight Changes
(National Institutes of Health)
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ClinicalTrials.gov: Obesity
(National Institutes of Health)
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ClinicalTrials.gov: Thinness
(National Institutes of Health)
Journal Articles References and abstracts from MEDLINE/PubMed (National Library of Medicine)
Find an Expert
- Find a Nutrition Expert (Academy of Nutrition and Dietetics)
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National Institute of Diabetes and Digestive and Kidney Diseases
Children
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Birth Weight: MedlinePlus Health Topic
(National Library of Medicine)
Also in Spanish
- Child and Teen BMI Categories (Centers for Disease Control and Prevention) Also in Spanish
- Overweight and Obesity (For Parents) (Nemours Foundation) Also in Spanish
- What "Being Overweight" Means (For Kids) (Nemours Foundation) Also in Spanish
Teenagers
- Staying at a Healthy Weight (For Teens) (Nemours Foundation)
- What's the Right Weight for My Height? (For Teens) (Nemours Foundation) Also in Spanish
Older Adults
- Healthy Lifestyles for Healthy Older Adults (Academy of Nutrition and Dietetics)
Patient Handouts
- Body mass index (Medical Encyclopedia) Also in Spanish
- Growth chart (Medical Encyclopedia) Also in Spanish
- Overweight (Medical Encyclopedia) Also in Spanish
- Weight gain - unintentional (Medical Encyclopedia) Also in Spanish
- Weight loss - unintentional (Medical Encyclopedia) Also in Spanish