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LEARNING OUTCOMES
Describe factors related to the increase in the prevalence of overweight and obesity among adults and children in the United States.
Explain the differences between overweight, overfat, and obesity.
Describe the use of body mass index (BMI) for population studies and its limitations for use with individuals.
Describe several health consequences of overweight and obesity.
Define the components of energy balance and describe the relationship of dietary intake and physical activity to each component.
Identify the hormones responsible for short- and long-term regulation of energy intake.
Describe the environmental and genetic factors that regulate body weight.
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ANCILLARY LINK
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VIGNETTE
Lucinda is a 45-year-old working mother of two daughters, ages 7 and 10. Like many women her age, she has experienced gradual weight gain since the birth of her children. Standing 5′2″ (1.6 m) tall and now weighing 160 pounds (73 kg), she is experiencing difficulty performing the everyday tasks associated with her busy lifestyle. Lucinda also was recently told by her physician that, in addition to being obese, she is starting to display other characteristics of metabolic syndrome, including hypertension and glucose intolerance.
Lucinda has "yo-yo dieted" in the past, usually resorting to very low-calorie diets, and does not exercise. She is convinced that her weight problem is genetic, because she and her mother look very similar despite their desire to be thinner. She is getting concerned that her daughters will also someday look just like her and does not want to live the rest of her life with health problems. Lucinda tries to "eat healthy," but resorts to eating at fast-food restaurants most days for the sake of convenience. This lifestyle has reduced her lean body mass over the years, and a recent body composition test conducted using a BOD POD revealed that she has 47% body fat.
How can a basic understanding of the physiology of obesity and the relationship between genetics and environment help Lucinda turn things around for herself, and also help her two young daughters avoid going down the same road as Lucinda and her mother?
The good news for Lucinda is that, because she was not an overweight child and is not above 170% of ideal body weight, it is unlikely that her obesity as an adult is due to adipocyte hyperplasia. The hypertrophic obesity that she has experienced is more likely due to poor dietary choices and being sedentary that have created years of positive energy balance, leading to excess calories that have been stored as triglyceride. The bad news is that years of poor dietary choices and lack of exercise have now led to adverse health conditions that will only get worse if she does nothing to ...