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Chapter 9 Energy Balance and Healthy Body Weight. Nutrition: Concepts & Controversies, 12e Sizer/Whitney. Learning Objectives. Delineate the health risks of too little and too much body fatness, with emphasis on central obesity and its associated health risks.
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Chapter 9Energy Balance and Healthy Body Weight Nutrition: Concepts & Controversies, 12e Sizer/Whitney
Learning Objectives • Delineate the health risks of too little and too much body fatness, with emphasis on central obesity and its associated health risks. • Describe the roles of BMR and several other factors in determining an individual’s daily energy needs.
Learning Objectives • Calculate the BMI when given height and weight information for various people, and describe the health implications of any given BMI value. • Compare and contrast the roles of the hormones ghrelin and leptin in appetite regulation, and name several other influences on both hunger and satiety.
Learning Objectives • Discuss the potential impact of “outside the body” factors on weight-control efforts. • Develop a weight-loss plan that includes controlled portions of nutrient-dense foods to produce gradual weight loss while meeting nutrient needs. • Discuss the role of physical activity in maintaining a healthy body composition.
Learning Objectives • Defend the importance of behavior modification in weight loss and weight maintenance over the long term. • Compare and contrast the characteristics of anorexia nervosa and bulimia nervosa, and provide strategies for combating eating disorders.
Introduction • Health risks • 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
What Are the Risks from Underweight? • Disadvantages • Siege or famine • Hospital stays • Wasting disease • Heart disease
What Are the Risks from Too Much Body Fat? • Obesity-related illnesses • Dying young • Obesity vs. smoking • Hypertension • Central obesity • Other risks
What Are the Risks from Central Obesity? • Risks of visceral fat • Subcutaneous fat • Adipokines • Regulate inflammatory processes • Central obesity causes a shift • Free fatty acids • Factors affecting fat distribution
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
Chronic Disease Risks According to BMI Values and Waist Circumference
The Body’s Energy Balance • Energy budget • Change in energy stores = energy in – energy out • Energy in • Foods and beverages • Energy out • Varies widely • Lifestyle and metabolism
The Body’s Energy Balance • Calorie needs • Monitor activity and weight • Energy output • Basal metabolism (BMR) • Voluntary activities • Thermic effect of food
The Body’s Energy Balance • Estimated energy requirements (EER) • Reference man and woman • Taller people • Need more energy • Energy need diminishes with age • DRI method • Gender, age, physical activity, body size and weight, and growth
Body Weight Versus Body Fatness • Body Mass Index (BMI) • Underweight • Overweight • Obesity • Risks follow racial lines • Drawbacks • Amount or location of fat • Diagnosis requirements
Measures of Body Composition and Fat Distribution • Body composition • Skin fold test • Underwater weighing • Bioelectrical impedance • Dual-energy X-ray absorptiometry • Each method has advantages and disadvantages
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
The Mystery of Obesity • Appetite • Initiates eating • Endorphins • Factors affecting appetite
The Mystery of Obesity • “Stop” signals • Satiation • Food in digestive tract • Hormones • Hypothalamus • Satiety • Regulates frequency of meals
The Mystery of Obesity • Leptin • Adipokine hormone • Appetite regulation • Leptin resistance • Energy nutrients • Protein provides most satiation
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
Outside-the-Body Causes of Obesity • Built environment • Can discourage physical activity • Food access • Food deserts • Fast food • Attain healthy body weight • Diet • Physical activity • Behavior change
How the Body Loses and Gains Weight • Tissue lost or gain • Depends on what you do • Water • Fat or muscle • Smoking • Hazards
Moderate Weight Loss Versus Rapid Weight Loss • Gradual weight loss is preferred • Fasting • Body adjustments • Sacrifice lean tissue • Death • Ketosis • Break down of fat molecules
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
Weight Gain • Energy-yielding nutrients contribute to body stores • Four sources of energy • Alcohol • Two types of energy stores • An excess of any food will become fat
Popular Fad Diets • Effectiveness • Both sides of the coin • Adequacy • To be achieved via food, not supplements • Safety • Personal responsibility
Achieving and Maintaining a Healthy Body Weight • Changing your body weight • What is your motivation? • Benefits of modest weight loss • Focus on health or fitness
What Diet Strategies Are Best for Weight Loss? • Aim for a realistic target • Reasonable goals • Specific and measurable objectives • Recommended weight loss • 1 to 2 pounds per week • Weight maintenance • Keep records • Plan your diet
What Diet Strategies Are Best for Weight Loss? • Realistic calorie intakes • Nutrient needs and caloric intake • Men • Women • Adequate diets • Choose sensibly • Consider a supplement • Calcium
What Diet Strategies Are Best for Weight Loss? • Manage portion sizes • Reduced-calorie foods • Read labels • Calorie calculations • Little daily decisions add up • Energy density • Low energy density • May not reflect nutrient density
What Diet Strategies Are Best for Weight Loss? • Artificial sweeteners • Soft drinks and milk consumption • Meal spacing • Hunger vs. appetite • Importance of breakfast • Night eating syndrome