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Obesity in Adolescents


Sharon Levy

, MD, MPH, Harvard Medical School

Last full review/revision Jul 2022| Content last modified Sep 2022
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Obesity is now twice as common among adolescents than it was 30 years ago and is one of the most common reasons for visits to adolescent clinics. Although fewer than one third of obese adults were obese as adolescents, most obese adolescents remain obese in adulthood.

Although most of the complications of obesity Obesity Obesity is excess body weight, defined as a body mass index (BMI) of ≥ 30 kg/m2. Complications include cardiovascular disorders (particularly in people with excess abdominal fat)... read more occur in adulthood, obese adolescents are more likely than their peers to have high blood pressure. Type 2 diabetes mellitus Diabetes Mellitus in Children and Adolescents Diabetes mellitus involves absence of insulin secretion (type 1) or peripheral insulin resistance (type 2), causing hyperglycemia. Early symptoms are related to hyperglycemia and include polydipsia... read more is occurring with increasing frequency in adolescents due to insulin resistance related to obesity. Because of society’s stigma against obesity, many obese adolescents have a poor self-image and become increasingly sedentary and socially isolated.

Etiology of Obesity in Adolescents

The factors that influence obesity among adolescents are the same as those among adults. Most cases are external (eg, consuming too many calories and/or a low-quality diet), often in conjunction with a sedentary lifestyle. Genetic influences are common, and responsible genes are now being identified ( see also Obesity and the Metabolic Syndrome Obesity and the Metabolic Syndrome ).

Parents may be concerned that obesity is the result of some type of endocrine disease, such as hypothyroidism Hypothyroidism Hypothyroidism is thyroid hormone deficiency. Symptoms include cold intolerance, fatigue, and weight gain. Signs may include a typical facial appearance, hoarse slow speech, and dry skin. Diagnosis... read more Hypothyroidism or hyperadrenocorticism, but such disorders are rarely the cause. Adolescents with weight gain caused by endocrine disorders are usually of small stature and have other signs of the underlying disorder.

Diagnosis of Obesity in Adolescents

  • Body mass index

Determination of the body mass index Diagnosis Obesity is excess body weight, defined as a body mass index (BMI) of ≥ 30 kg/m2. Complications include cardiovascular disorders (particularly in people with excess abdominal fat)... read more (BMI) is an important aspect of physical assessment. Adolescents whose BMI is ≥ the 95th percentile for their age and sex are obese.

Primary endocrine (eg, hyperadrenocorticism, hypothyroidism) or metabolic causes are uncommon but should be ruled out if height growth slows significantly. If the child is short and has hypertension, Cushing syndrome Cushing Syndrome Cushing syndrome is a constellation of clinical abnormalities caused by chronic high blood levels of cortisol or related corticosteroids. Cushing disease is Cushing syndrome that results from... read more Cushing Syndrome should be considered.

Treatment of Obesity in Adolescents

  • Healthy eating and exercise habits

Despite many therapeutic approaches, obesity is one of the most difficult problems to treat, and long-term success rates remain low. Intervention for obese adolescents should be focused on developing healthy eating and exercise habits rather than on losing a specific amount of weight. Caloric intake is reduced by

  • Establishing a well-balanced diet of ordinary foods

  • Making permanent changes in eating habits

Calorie burning is increased by

  • Increasing physical activity

Counseling to help adolescents cope with their problems, including poor self-esteem, may be helpful.

Drugs that help reduce weight are generally not used during adolescence because of concerns about safety and possible misuse. One exception is for obese adolescents with obesity who have a strong family history of type 2 diabetes. They are at high risk of developing diabetes. The drug metformin, which is used to treat diabetes, may help them lose weight and also lower their risk of becoming diabetic.

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