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  1. Describe the various models of body composition, including how they are applied in body composition assessment.

  2. List the determinants of body composition and describe how they affect the accuracy of body composition assessment across different populations.

  3. Identify the health risks of having too much or too little body fat.

  4. Explain the difference between assessments that measure body weight and those that assess body composition.

  5. Calculate ideal body weight based on percent body fat.

  6. Calculate body mass index.

  7. Describe commonly used techniques for body composition assessment and explain appropriate uses for each.

  8. Give general guidelines for follow-up body composition assessment measures.


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  • Suzanne is a 60-year-old woman who was recently diagnosed with type 2 diabetes. At her last doctor's visit, Suzanne expressed concern about the accuracy of the diagnosis because she had always heard that type 2 diabetes is associated with obesity, and she is not obese. In fact, although she is not physically active, Suzanne has a slender build and has never had a weight problem. Over the past 15 years, Suzanne has gained about 7 pounds, but even with added weight, she wears the same size clothing she has always worn throughout her adulthood. Suzanne's physician assures her that his diagnosis is correct and, in addition to prescribing her oral diabetes medication and referring her to a registered dietitian, he encourages her to start a regular exercise program that focuses on improving her body composition.

    How is it possible that a slender person, like Suzanne, would need to take actions to improve his or her body composition?

  • Suzanne has several individual characteristics that put her at increased risk for an unfavorable body composition. Her age, sex, and physical-activity status set the stage for loss of FFM, and hence higher FM. To address Suzanne's concerns about her type 2 diabetes diagnosis, her doctor refers her to the hospital wellness center to undergo a body composition assessment. There she meets Alonzo, a laboratory technician who performs a dual-energy x-ray absorptiometry (DEXA) scan, which will provide a clearer picture of Suzanne's body composition.

  • Before her body composition assessment, Alonzo helps Suzanne calculate her BMI. She is 5′4″ and weighs 115 lb, which places her toward the low end of the normal weight category, with a BMI of 18.9 kg/m2. This further confuses Suzanne, particularly because her doctor told her to work on improving her body composition and her BMI confirms that she does not have a "weight problem."

  • According to Suzanne's DEXA scan, her %BF is 32.1, which places her in the obese category. While difficult for Suzanne to accept, she admits that her poor nutrition habits and lack of physical activity have ...

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