Chapter 8 Flashcards
Energy Balance
Energy balance: Equilibrium of energy intake (from food/drinks) and expenditure (via metabolism and activities).
Weight changes result from imbalance; excess energy is stored as fat. Classic rule: 1 lb of fat ≈ 3500 kcal excess, but varies by gender, weight, and body composition.
Bomb Calorimeter
Measuring Food Energy
Bomb Calorimeter: Measures heat energy released from burning food.
Physiological value
Measuring Food Energy
Physiological value – kcalories the body actually derives from food
– Body unable to metabolize all the macronutrients completely
Hunger
Food Intake Mechanisms
Hunger: Physiological need triggered by the hypothalamus.
Satiety
Food Intake Mechanisms
Satiety: Fullness post-meal; regulates intervals between meals.
Satiation
Food Intake Mechanisms
Satiation: Fullness during eating; controls meal size.
Appetite
Food Intake Mechanisms
Appetite: Desire for food, triggered by sensory cues.
Psychological triggers
Factors Influencing Eating
Psychological triggers: Boredom, stress.
External cues
Factors Influencing Eating
External cues: Meal timing, food availability.
Environmental and cognitive factors
Factors Influencing Eating
Environmental and cognitive factors: Portion sizes, social events, memories.
Protein
Nutrients & Satiety
Protein: Most satiating.
Fructose
Nutrients & Satiety
Fructose: Stimulates appetite.
High-fiber foods
Nutrients & Satiety
High-fiber foods: Enhance satiety.
High-fat foods
Nutrients & Satiety
High-fat foods: Flavorful and increase satiety when digested, releasing hormones (e.g., cholecystokinin).
BMR
Energy Expenditure Components
Basal Metabolism (BMR): Energy for basic functions; influenced by weight, lean mass, age.
Physical Activity
Energy Expenditure Components
Physical Activity: Most variable; affected by weight, muscle mass, activity type.
Thermic Effect of Food
Energy Expenditure Components
Thermic Effect of Food: Energy for digestion, transport, storage; varies by meal composition.
Factors Affecting BMR
Includes body composition, age, gender, growth status, physical activity levels.
Adaptation
Adaptive Thermogenesis
Adaptation: Body’s response to extreme conditions (e.g., burns, cold, overeating).
Variable energy costs
Adaptive Thermogenesis
Variable energy costs: Not typically factored in for most people.
Estimating Energy Requirements
Factors: Gender, growth, age, activity level, body composition (height/weight).
Healthy Body Weight
Healthy Body
Reflects not just societal standards but personal health.
Acceptance of individual healthy weights is encouraged.
Disease risks
Body Fat and Distribution
Disease risks: Linked to amount and location of body fat.
Visceral vs. Subcutaneous Fat
Body Fat and Distribution
Visceral vs. Subcutaneous Fat:
Visceral fat (around organs): Linked to heart disease, diabetes (central obesity). Subcutaneous fat (around hips/thighs): Lower risk.
Waist Circumference
Risk indicators: >40 inches (men), >35 inches (women) signal central obesity.
Waist-to-hip ratio is a valuable measure for health risk.
Methods of Assessing Body Fat
Common Techniques: Includes BMI, waist circumference, and other body composition methods.
Underweight risks
Health Risks of Body Weight and Fat
Underweight risks: Increased vulnerability to illness, infertility, osteoporosis.
Overweight/Obese risks
Health Risks of Body Weight and Fat
Obesity classified as a disease, correlating with health issues, disability, medical costs.
Disease risks include cardiovascular disease, Type II diabetes, and cancer risk proportional to obesity duration and level.
