Energy Balance and Body Weight Regulation Chapter 09
Energy Balance and Body Weight Regulation Chapter 09
What Is Energy Balance? • Energy balance • Energy intake equals energy expenditure • Body weight is stable • Positive energy balance • Weight gain • Growth and development • Negative energy balance • Weight loss • Components of weight lost
The Three States of Energy Balance
What Is Energy Balance? • Adipose tissue • Number and size of adipocytes • Hypertrophic growth • Hyperplastic growth • Adipocytes produce adipokines • Regulation of energy balance • Endocrine-like organ
Hypertrophic & Hyperplastic Growth of Adipose Tissue
What Is Energy Balance? • Adipose tissue • Location • Visceral adipose tissue (VAT) • Between internal organs in the torso • Weight-related health problems • Waist circumference standards • Waist-to-hip ratio • Subcutaneous adipose tissue (SCAT) • Around thighs, hips, and buttocks
Cross-Section of the Upper Body
What Factors Influence Energy Intake? • Eating behavior • Psychological, physical, social, and cultural forces • Hypothalamus • Hunger • Physiological drive • Satiety • Physiological response • Signals – neurotransmitters
What Factors Influence Energy Intake? • GI tract • Gastric distention • Satiety trigger • High-volume foods • Post-absorptive mechanism • Glucose • Fat • Hormones • Ghrelin
What Factors Influence Energy Intake? • Psychological factors • Food aversions • Strong psychological dislike for a food • Long lasting • Appetite • Psychological longing for a food • Sensory factors • Emotional states • Food craving
Regulation of Short-Term Food Intake
Weight-Loss Surgery • Bariatric surgery • Gastric banding • Divides stomach into two regions • Gastric bypass • Reduces size of stomach • Effectiveness • Risks
Types of Weight-Loss Surgery
What Determines Energy Expenditure? • Total energy expenditure (TEE) • Basal metabolism • Physical activity • Thermic effect of food • Adaptive thermogenesis • Adapt to changes in the environment & • physiological conditions Nonexercise activity thermogenesis Spontaneous movements •
Major Components of TEE
What Determines Energy Expenditure? • Basal metabolism • Basic, involuntary life functions • Basal metabolic rate (BMR) • kcal/hour • 50 to 70 percent of TEE • Factors affecting BMR
Factors Affecting BMR
What Determines Energy Expenditure? • Physical activity • 15 to 30 percent of TEE • Factors influencing energy expenditure • Thermic effect of food • Digest, absorb, and metabolize nutrients • Amount of food consumed • Types of nutrients present in food • 5 to 10 percent of TEE
How Are Body Weight & Composition Assessed? • Overweight • Excess weight • Obese • Excess fat • Body weight assessment • Height-weight tables • Body mass index (BMI) • Criteria categories
Relationship between BMI & Weight-Related Mortality
How Are Body Weight & Composition Assessed? • Body composition • Fat compartment • Stored triglycerides and supporting • • • structures Lean compartment Muscle, water, and bone Influential factors Recommended body fat levels •
Obesity Classifications Based on Percent Body Fat
How Are Body Weight & Composition Assessed? • Measuring body composition • Health risks of obesity • Hydrostatic weighing • Fat density • Dual-energy x-ray absorptiometry (DEXA) • Gold standard • Bioelectrical impedance • Skinfold thickness • Caliper
Health Problems Associated with Obesity
Methods Used to Estimate Body Composition
Genetics vs. Environment: What Causes Obesity? • Overweight and obesity trends in U. S. • Nutrition transition • Lifestyle and genetic factors • Eating habits • Daily caloric intake has increased • Societal and cultural norms • Portion sizes; fast food; visual cues • Sociodemographic & psychological influences
Estimated Prevalence of Obesity in the 1970 s & 2007 -2008
Genetics vs. Environment: What Causes Obesity? • Sedentary lifestyle • Trends in physical activity • Physical activity • Exercise • Genetics • Ob/ob mouse – obese mouse • Leptin • Db/db mouse – diabetic mouse • Leptin receptor
How Are Energy Balance and Body Weight Regulated? • Set point theory • Hormones circulating in the blood regulate body weight • Communication about adipose tissue in the body • Leptin • Communicates energy reserves to the brain • Reflects changes in adipose tissue • Defects in leptin-signaling pathways
Leptin and Body Weight Regulation
What Is the Best Approach to Weight Loss? • There is no quick and easy way to lose • weight Popular weight loss plans • Specific rules • Challenge to keep weight off • Numerous different weight-loss products available
What Is the Best Approach to Weight Loss? • Healthy food choices • Lasting lifestyle changes • Choose a balance diet • Nutrient-dense foods • Moderately high level of physical activity
What Is the Best Approach to Weight Loss? • Three important components • Set reasonable goals • Slow and steady weight loss • Choose nutritious foods in moderation • Limit trans fatty acids and SFAs • Hunger and satiety cues • Portion sizes • Increase energy expenditure • Recommended activity levels
Behaviors Associated with Healthy Weight Management
What Is the Best Approach to Weight Loss? • Successful weight loss characteristics • Incorporation of diet and physical activity • Ate breakfast regularly • Monitored their weight regularly • Macronutrient distribution • Controversy regarding carbohydrate intake • AMDRs
What Is the Best Approach to Weight Loss? • High-carbohydrate, low-fat diets • 65 to 75 percent of calories from carbohydrates • Prevent obesity • Fat has more calories per gram than carbs • Fat adds flavor and can contribute to overconsumption of food • Excess fat calories are stored more efficiently • Types of carbohydrates consumed
Caloric Distribution of High- & Low -Carb Diets Compared to AMDRs
What Is the Best Approach to Weight Loss? • Low-carbohydrate weight-loss diets • Examples • Differences in excluded foods • Weight loss • Safety and effectiveness • Short-term • Long-term
What Is the Best Approach to Weight Loss? • Total calories vs. AMDRs • Reducing caloric intake • Most critical component of weight loss • Maintaining neutral energy balance is complex • Healthy eating • Physical activity
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