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  • Define obesity.

  • Describe the populations most affected by obesity.

  • Describe the health consequences of obesity.

  • Discuss the difficulties with losing weight, including patient and health-care provider challenges.

  • Suggest ways for health-care providers to discuss weight loss with patients.

  • Describe strategies for weight loss.

Esmeralda, a 15-year-old girl, requests a written excuse to skip school physical education classes. Her body mass index (BMI) of 32 reveals that she is in the highest weight category for girls her age. She often skips breakfast and eats most meals in front of the television. Her family members are also obese and have type II diabetes.

Worldwide young and old are being affected by obesity and its complications. Indeed, the obesity “epidemic” may be one of the most significant challenges to global, as well as national health. Paradoxically, poor families are particularly affected because of coexisting undernutrition, lack of resources to eat healthily, and inadequate venues for exercise.

Tackling the obesity epidemic will be not an easy feat because its causes are complex–bridging societal issues (such as governmental subsidies of high caloric food), and personal ones (how active people are). Although health-care providers need to be engaged in the wider public health and community efforts addressing obesity, helping patients as they strive to lose weight or suffer from its consequences remains equally important. This chapter discusses both the challenges and strategies of addressing obesity.


The most widely used classification system for obesity–an abnormal accumulation of body fat–in adults is the body mass index (BMI). The BMI estimates the amount of body fat through a calculation that adjusts weight for height (see “Resources” for online BMI calculator). A normal adult BMI is between 18.5 and 24.9. BMIs between 25 and 29.9 indicate overweight, a BMI greater than 30 indicates obesity, and a BMI greater than 40 indicates extreme obesity. Although health implications of BMI cutoffs vary across ethnic groups,1 it is accepted that increasing BMI is associated with an increased risk of death from cancers and cardiovascular disease. Obesity was most strongly associated with an increased risk of death among never smokers who had no history of disease.2,3

BMI for children, unlike adults, is both age and gender specific because children’s bodies change dramatically as they grow, and these changes differ between boys and girls. Terminology for classifying BMI in children has changed and now the language is more consistent with the adult classification (Box 37-1).4 Because in older adolescents a BMI of 95th percentile is higher than the adult cut point of 30 kg/m2, obesity in this population is defined as BMI > 95 percentile or BMI > 30 kg/m2, whichever is lower.4

Box 37-1. Classification System for Obesity

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