Chapter 9 Energy Balance and Healthy Body Weight Nutrition: Concepts & Controversies, 12e Sizer/Whitney
Introduction Health risks Weight “control” Body composition Overweight Underweight Weight “control” Focus on weight Focus on controlling weight Focus on short-term endeavors Body composition
The Problems of Too Little or Too Much Body Fat U.S. prevalence Underweight Overweight Epidemic Children and adolescents
Increasing Prevalence of Obesity
Adult Obesity and Overweight Compared with Healthy People Target
Underweight, Overweight, and Mortality
What Are the Risks from Too Much Body Fat? Obesity-related illnesses Dying young Obesity vs. smoking Hypertension Central obesity Other risks
Visceral Fat and Subcutaneous Fat
How Fat Is Too Fat? Evaluate health risks of obesity Body mass index (BMI) Waist circumference Disease risk profile Social costs of being overfat Economic costs of being overfat
The Body’s Energy Balance Calorie needs Monitor activity and weight Energy output Basal metabolism (BMR) Voluntary activities Thermic effect of food
Components of Energy Expenditure
Body Weight Versus Body Fatness Body Mass Index (BMI) Underweight Overweight Obesity Risks follow racial lines Drawbacks Amount or location of fat Diagnosis requirements
Measuring Waist Circumference
Measures of Body Composition and Fat Distribution Skin fold test Underwater weighing Bioelectrical impedance Dual-energy X-ray absorptiometry Each method has advantages and disadvantages
Average Body Composition of Men and Women
How Much Body Fat Is Ideal? Healthy BMI range Man: 12 to 20 percent Woman: 20 to 30 percent Declaration of being overfat Men age 40 and younger Men over age 40 Women age 40 and younger Women over age 40
The Mystery of Obesity Obesity’s cause remains elusive Hunger Satiety Response to physiological need Chemical messengers Stomach hormone Ghrelin Stomach capacity
Inside-the-Body Causes of Obesity Metabolic theories Variations in ease of body fat gain or loss Variety of theories Genetics Influence tendency to gain weight or stay lean Environmental factors
Outside-the-Body Causes of Obesity External cues to overeating Available foods Human sensations Larger portions Physical inactivity Nonexercise activity thermogenesis (NEAT) Inactivity epidemic Sitting still and death from heart disease
Feasting and Fasting
Moderate Weight Loss Versus Rapid Weight Loss Short-term fasting Seems to be tolerated Effects of deprivation Overeat or binge eating Weight loss technique Slowing of metabolism Low-carbohydrate diets DRI minimum carbohydrate intake level
Examples of Energy Density
Introduction Eating disorders Young women Beginnings of disorders Anorexia nervosa Bulimia nervosa Binge eating disorder Young women All people Beginnings of disorders
Anorexia Nervosa Characteristics Role of the family Self-starvation Cannot recognize condition Role of the family Self-starvation Physical perils Damage to whole body Death Treatment
Bulimia Nervosa Characteristics Role of the family More prevalent than anorexia nervosa Role of the family Binge eating and purging Stages of a binge Methods for purging Physical and psychological perils Treatment
The Cycle of Bingeing, Purging, and Negative Self-Perception