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Dieting and Obesity. Setpoint Theory of Weight. Setpoint: what an individual weighs when s/he eats a “normal” amount of food in a “normal” way May not be the same as one’s psychologically ideal weight. Basal Metabolic Rate. Definition Variations Factors that increase or decrease BMR.
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Setpoint Theory of Weight • Setpoint: what an individual weighs when s/he eats a “normal” amount of food in a “normal” way • May not be the same as one’s psychologically ideal weight
Basal Metabolic Rate • Definition • Variations • Factors that increase or decrease BMR
Keys Study on Starvation (1950) • Purpose • Subjects • Method
Effects of Starvation • Physical responses • Appetitive responses • Psychological responses
Sims et al. Study on Weight Gain (1968) • Purpose • Subjects • Method
Effects of Attempting to Gain Weight • Increases in body temperature and perspiration • Post-experiment weight stabilization
Heritability Estimates from Twin Studies Breast Cancer 45% Coronary Heart Disease 49% Epilepsy 50% Alcoholism 57% Schizophrenia 68% Height 80% Weight 81%
Overweight and Obese • Body Mass Index guidelines • Health profession’s insistence on treating obesity
Addictions Model of Obesity • Food as a drug • Effects on mesocorticolimbic system – the dopamine pathway • Sensitivity to reward • Poor decision making
Dieting Methods • Fasting • Liquid protein • Very low calorie diets • Low calorie diets • Low fat diets • Commercial weight loss programs
Quote: “If a cure from obesity is defined as a reduction to ideal weight and maintenance of that weight for 5 years, a person is more likely to recover from most forms of cancer than from obesity” Kelly Brownell
Medical Complications of Obesity • Prospective studies • Cross-sectional studies
Mortality • Selective citations • Protective factors of overweight mostly ignored
Summary • Negative impact of obesity on longevity and health has been overstated • Dieting is an ineffective treatment for obesity • Dieting may do more harm than help
Restrained vs. Unrestrained Eaters • Weight • Cognitive Performance • Mood • Self-Esteem • Eating Behaviour