Chapter 14 Energy Balance and Body Composition
Energy Balance: The relationship between energy intake (from food and beverages) and energy expenditure (through basal metabolism, physical activity, and thermic effect of food).
Positive Energy Balance: When energy intake exceeds energy expended, leading to weight gain. This can occur during:
Pregnancy
Childhood
Adolescence
Increased muscle mass or adipose tissue
Negative Energy Balance: When energy expended exceeds energy intake, leading to weight loss. This can occur due to:
Reduced food intake
Increased physical activity
Loss of fat, muscle, glycogen, or water
Kilocalories in Food:
Measured using a bomb calorimeter, which provides physiological fuel values.
Nutrition analysis software or food composition tables can also be used.
Kilocalories per Gram:
Carbohydrates: 4 kcal/gram
Protein: 4 kcal/gram
Fat: 9 kcal/gram
Alcohol: 7 kcal/gram
Components of Energy Expenditure:
Basal metabolism
Thermic effect of food (TEF)
Thermic effect of exercise (TEE)
Adaptive thermogenesis
Total Daily Energy Expenditure (TDEE): Total kilocalories needed to meet daily energy requirements.
Basal Metabolic Rate (BMR): Energy spent to meet the body's basic physiological needs.
Influenced by factors such as lean body mass, age, gender, body size, genes, ethnicity, stress, thyroid hormone levels, nutritional state, environmental temperature, and caffeine/nicotine intake.
Resting Metabolic Rate (RMR): Often used instead of BMR as it is easier to measure.
Thermic Effect of Exercise (TEE): Energy expended during physical activity.
Depends on the activity type, duration, and body weight.
Non-Exercise Activity Thermogenesis (NEAT): Energy expended from activities not considered exercise.
Thermic Effect of Food (TEF): Energy used to process macronutrients and extract kilocalories from food.
Accounts for about 10% of kilocalories consumed.
Higher for protein than carbohydrates or fats.
Influenced by nutrient type, meal composition, alcohol intake, age, and athletic training status.
Adaptive Thermogenesis: Body's regulation of heat production in response to environmental changes (stress, temperature, diet).
Direct Calorimetry: Measures energy expenditure by assessing body heat loss within a metabolic chamber.
Indirect Calorimetry: Estimates energy expenditure by measuring oxygen consumption and carbon dioxide production.
Simple Calculations: Used to estimate total energy expenditure based on age, gender, height, weight, and physical activity level.
Estimated energy requirement (EER)
Harris–Benedict equation for RMR
Body Composition: Ratio of fat tissue to lean body mass (muscle, bone, organs).
Expressed as percent body fat.
Important for assessing health risks related to body fat.
Types of Body Fat:
Essential fat: Necessary for body functions. Higher in women (12%) than men (3%).
Stored fat: Found in adipose tissue (subcutaneous under the skin and visceral around organs).
Adipose Tissue: Releases fat during negative energy balance (weight loss) and accumulates fat during positive energy balance (weight gain).
Brown Adipose Tissue (BAT): Specialized fat cells that generate heat, contain more mitochondria, and rich in blood.
Central Obesity (Android Obesity): Excess visceral fat in the abdomen, increasing risk for heart disease, diabetes, and hypertension.
Gynoid Obesity: Excess fat around the thighs and buttocks, more common in women.
Hydrostatic Weighing: Assesses body volume by underwater weighing (2-3% error margin).
Air Displacement Plethysmography (BodPod): Measures air displacement (3% error margin).
Dual-Energy X-ray Absorptiometry (DEXA): Measures bone density and body mass (1-4% error margin).
Bioelectrical Impedance Analysis (BIA): Measures resistance to low-energy current through muscle and body fat.
Skinfold Caliper: Measures fat in various locations, accurate with trained technicians.
Waist Circumference: Indicates health risk, >35 inches in women and >40 inches in men indicates increased risk.
Height and Weight Tables: Provide a healthy weight range based on height, gender, and frame size. Less commonly used now.
Body Mass Index (BMI): Calculates body weight in relation to height.
Used to screen for disease risk.
Obese individuals have a higher risk of premature death.
Not always accurate for athletes, older adults, or individuals less than 5 feet tall.
Underweight: Increases risk of anemia, osteoporosis, heart irregularities, amenorrhea, depression, anxiety, infections, temperature regulation issues, and premature death.
Overweight: Increases risk of heart disease, hypertension, stroke, gallstones, hyperlipidemia, sleep apnea, reproductive problems, and certain cancers.
Disordered Eating: Abnormal and potentially harmful eating patterns, such as refusing to eat, compulsive eating, binge eating, restrictive eating, vomiting, and abusing diet pills.
Eating Disorders: Psychological illnesses with specific criteria, including anorexia nervosa, bulimia nervosa, binge eating disorder, orthorexia, and night eating syndrome.
Anorexia Nervosa: Characterized by self-starvation, excessive weight loss, fear of gaining weight, and health consequences like electrolyte imbalances, hair loss, and nutrient deficiencies.
Bulimia Nervosa: Characterized by binge eating followed by purging, with health consequences such as esophageal tears, tooth decay, and electrolyte imbalances.
Binge Eating Disorder: Characterized by recurrent binge eating without purging, leading to health issues like high blood pressure and heart disease.
Orthorexia: Obsession with healthy eating, often leading to restrictive diets and potentially developing into anorexia.
Night Eating Syndrome: Eating a majority of daily kilocalories after the evening meal and during the night, often associated with low self-esteem, depression, and stress.
Multidisciplinary Approach: Involves psychological, medical, and nutrition professionals. Treatment includes meal planning, food journals, identifying triggers, and recognizing hunger and fullness cues.
Energy Balance: The relationship between energy intake (from food and beverages) and energy expenditure (through basal metabolism, physical activity, and thermic effect of food).
Positive Energy Balance: When energy intake exceeds energy expended, leading to weight gain. This can occur during:
Pregnancy
Childhood
Adolescence
Increased muscle mass or adipose tissue
Negative Energy Balance: When energy expended exceeds energy intake, leading to weight loss. This can occur due to:
Reduced food intake
Increased physical activity
Loss of fat, muscle, glycogen, or water
Kilocalories in Food:
Measured using a bomb calorimeter, which provides physiological fuel values.
Nutrition analysis software or food composition tables can also be used.
Kilocalories per Gram:
Carbohydrates: 4 kcal/gram
Protein: 4 kcal/gram
Fat: 9 kcal/gram
Alcohol: 7 kcal/gram
Components of Energy Expenditure:
Basal metabolism
Thermic effect of food (TEF)
Thermic effect of exercise (TEE)
Adaptive thermogenesis
Total Daily Energy Expenditure (TDEE): Total kilocalories needed to meet daily energy requirements.
Basal Metabolic Rate (BMR): Energy spent to meet the body's basic physiological needs.
Influenced by factors such as lean body mass, age, gender, body size, genes, ethnicity, stress, thyroid hormone levels, nutritional state, environmental temperature, and caffeine/nicotine intake.
Resting Metabolic Rate (RMR): Often used instead of BMR as it is easier to measure.
Thermic Effect of Exercise (TEE): Energy expended during physical activity.
Depends on the activity type, duration, and body weight.
Non-Exercise Activity Thermogenesis (NEAT): Energy expended from activities not considered exercise.
Thermic Effect of Food (TEF): Energy used to process macronutrients and extract kilocalories from food.
Accounts for about 10% of kilocalories consumed.
Higher for protein than carbohydrates or fats.
Influenced by nutrient type, meal composition, alcohol intake, age, and athletic training status.
Adaptive Thermogenesis: Body's regulation of heat production in response to environmental changes (stress, temperature, diet).
Direct Calorimetry: Measures energy expenditure by assessing body heat loss within a metabolic chamber.
Indirect Calorimetry: Estimates energy expenditure by measuring oxygen consumption and carbon dioxide production.
Simple Calculations: Used to estimate total energy expenditure based on age, gender, height, weight, and physical activity level.
Estimated energy requirement (EER)
Harris–Benedict equation for RMR
Body Composition: Ratio of fat tissue to lean body mass (muscle, bone, organs).
Expressed as percent body fat.
Important for assessing health risks related to body fat.
Types of Body Fat:
Essential fat: Necessary for body functions. Higher in women (12%) than men (3%).
Stored fat: Found in adipose tissue (subcutaneous under the skin and visceral around organs).
Adipose Tissue: Releases fat during negative energy balance (weight loss) and accumulates fat during positive energy balance (weight gain).
Brown Adipose Tissue (BAT): Specialized fat cells that generate heat, contain more mitochondria, and rich in blood.
Central Obesity (Android Obesity): Excess visceral fat in the abdomen, increasing risk for heart disease, diabetes, and hypertension.
Gynoid Obesity: Excess fat around the thighs and buttocks, more common in women.
Hydrostatic Weighing: Assesses body volume by underwater weighing (2-3% error margin).
Air Displacement Plethysmography (BodPod): Measures air displacement (3% error margin).
Dual-Energy X-ray Absorptiometry (DEXA): Measures bone density and body mass (1-4% error margin).
Bioelectrical Impedance Analysis (BIA): Measures resistance to low-energy current through muscle and body fat.
Skinfold Caliper: Measures fat in various locations, accurate with trained technicians.
Waist Circumference: Indicates health risk, >35 inches in women and >40 inches in men indicates increased risk.
Height and Weight Tables: Provide a healthy weight range based on height, gender, and frame size. Less commonly used now.
Body Mass Index (BMI): Calculates body weight in relation to height.
Used to screen for disease risk.
Obese individuals have a higher risk of premature death.
Not always accurate for athletes, older adults, or individuals less than 5 feet tall.
Underweight: Increases risk of anemia, osteoporosis, heart irregularities, amenorrhea, depression, anxiety, infections, temperature regulation issues, and premature death.
Overweight: Increases risk of heart disease, hypertension, stroke, gallstones, hyperlipidemia, sleep apnea, reproductive problems, and certain cancers.
Disordered Eating: Abnormal and potentially harmful eating patterns, such as refusing to eat, compulsive eating, binge eating, restrictive eating, vomiting, and abusing diet pills.
Eating Disorders: Psychological illnesses with specific criteria, including anorexia nervosa, bulimia nervosa, binge eating disorder, orthorexia, and night eating syndrome.
Anorexia Nervosa: Characterized by self-starvation, excessive weight loss, fear of gaining weight, and health consequences like electrolyte imbalances, hair loss, and nutrient deficiencies.
Bulimia Nervosa: Characterized by binge eating followed by purging, with health consequences such as esophageal tears, tooth decay, and electrolyte imbalances.
Binge Eating Disorder: Characterized by recurrent binge eating without purging, leading to health issues like high blood pressure and heart disease.
Orthorexia: Obsession with healthy eating, often leading to restrictive diets and potentially developing into anorexia.
Night Eating Syndrome: Eating a majority of daily kilocalories after the evening meal and during the night, often associated with low self-esteem, depression, and stress.
Multidisciplinary Approach: Involves psychological, medical, and nutrition professionals. Treatment includes meal planning, food journals, identifying triggers, and recognizing hunger and fullness cues.
