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Questions and Answers
At what age does bone density typically continue to increase until it begins to decline?
At what age does bone density typically continue to increase until it begins to decline?
Which physiological change is associated with the decline of estrogen during menopause in women?
Which physiological change is associated with the decline of estrogen during menopause in women?
What is the general trend regarding physical working capacity in older adults?
What is the general trend regarding physical working capacity in older adults?
How does body composition typically change as adults age?
How does body composition typically change as adults age?
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What age range defines middle adulthood?
What age range defines middle adulthood?
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What percentage of weight lost through calorie restriction consists of fat-free mass?
What percentage of weight lost through calorie restriction consists of fat-free mass?
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What is the predicted weight change for a 100 kg man on a -480 kcal/day regimen after one year, according to dynamic modeling?
What is the predicted weight change for a 100 kg man on a -480 kcal/day regimen after one year, according to dynamic modeling?
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How is greater adiposity related to expected weight loss for the same change in energy intake?
How is greater adiposity related to expected weight loss for the same change in energy intake?
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What is the standard rule for weight loss regarding calorie restriction?
What is the standard rule for weight loss regarding calorie restriction?
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What percentage of weight lost through a combination of calorie restriction and exercise is made up of fat mass?
What percentage of weight lost through a combination of calorie restriction and exercise is made up of fat mass?
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What factor does dynamic modeling of human energy regulation NOT take into account?
What factor does dynamic modeling of human energy regulation NOT take into account?
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What is the calorie intake per day expected to achieve a weight loss of -500 kcal/day?
What is the calorie intake per day expected to achieve a weight loss of -500 kcal/day?
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Which component has the largest part in overall energy expenditure?
Which component has the largest part in overall energy expenditure?
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What is the main limitation of direct calorimetry?
What is the main limitation of direct calorimetry?
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Which of the following factors does NOT impact energy needs?
Which of the following factors does NOT impact energy needs?
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Which equation is validated as more accurate for estimating resting energy expenditure in overweight and obese adults?
Which equation is validated as more accurate for estimating resting energy expenditure in overweight and obese adults?
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How does indirect calorimetry determine resting energy expenditure?
How does indirect calorimetry determine resting energy expenditure?
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What is a major limitation of doubly labeled water as a method for measuring energy expenditure?
What is a major limitation of doubly labeled water as a method for measuring energy expenditure?
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Which of the following is a characteristic of the thermic effect of food (TEF)?
Which of the following is a characteristic of the thermic effect of food (TEF)?
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What factor is included in calculating the resting energy expenditure for males?
What factor is included in calculating the resting energy expenditure for males?
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Study Notes
Adult Nutrition Lecture 22
- Learning Objectives: Describe and discuss physiological changes in adults, key components determining energy needs and expenditure, methodologies to determine energy needs, and methods to adjust energy needs for weight loss.
Definition of Adult Stages
- Early Adulthood: 20-39 years
- Middle Adulthood: 40s
- "Sandwich" Generation (50s): Often multigenerational caregivers, frequently concerned with diet, physical activity, smoking, and body weight.
- Later Adulthood (65+): This stage is not defined as a specific age range
- Health concerns (diet, physical activity, smoking, body weight) are frequently prevalent
Nutritional Factors Influencing Disease
- Cancer: Low fruit and vegetable intake, low antioxidant intake (especially vitamins A & C), low whole grains and fiber, high dietary fat intake, nitrosamines (burnt/charred food), pickled/fermented food, alcohol.
- Heart Disease: High saturated fat (>10% calories), trans-fatty acid intake, dietary cholesterol (>300 mg), low fruit/vegetable intake, low antioxidants, low whole grains, no or excess alcohol intake, high sodium intake, low potassium, low dairy intake, high waist circumference (men >40 in, women >35 in)
- Obesity: Caloric intake exceeding needs, unstructured eating, frequent fast-food consumption, high fat intake, sugar-sweetened beverages, energy-dense, low-nutrient food choices.
- Diabetes: Atherogenic and obesogenic diets. Obesity (BMI >30) and physical inactivity are also risk factors. Moderate alcohol intake may reduce risk in middle-aged adults (men >45, women >55).
Physiological Changes - Bone Mass
- Bone growth stops in the 20s.
- Bone density continues to increase until 30.
- Bone loss begins around 40.
Physiological Changes - Body Composition
- Positive energy balance leads to increased weight and adiposity.
- Fat redistribution, with central and intra-abdominal fat increasing, while subcutaneous fat decreases.
- Dexterity and flexibility decline with age.
Physiological Changes - Hormones (Women)
- Decline of estrogen (menopause).
- Increased abdominal fat.
- Increased risk of cardiovascular disease and accelerated bone loss.
Physiological Changes - Physical Capacity
- Physical working capacity declines 5-10% per decade in older adults, particularly non-linearly with musculoskeletal disease, obesity, and other conditions affecting capacity.
Physiological Changes - Gut Microbiome
- Gut dysbiosis is a common change in aging, with a shift between microbial components.
- The aging process is characterized by altered microbial composition.
How is Energy Need Determined?
- Basal Metabolic Rate (BMR): Daily energy expenditure for involuntary processes, often measured as REE or RMR. Largely the largest component of energy expenditure.
- Thermic Effect of Food (TEF): Energy expenditure attributed to food metabolism.
- Physical Activity Energy Expenditure (PAEE): Energy expenditure related to exercise thermogenesis and non-exercise activity thermogenesis (NEAT).
Factors Affecting Energy Needs
- Lean body mass
- Health status
- Age
- Gender/body size
- Activity levels
- Hormones
- Individual variation
Determining Energy Needs – Equations
- Mifflin-St. Jeor Equation: A more accurate formula for REE than the Harris-Benedict equation, particularly for overweight and obese adults. Specific equations are provided for males and females. Activity factors for different activity levels are provided.
Determining Energy Needs - Calorimetry
- Direct Calorimetry: Measures heat production in a chamber to determine energy expenditure. Accurate but expensive and confines the subject to the chamber environment.
- Indirect Calorimetry: Calculates heat produced based on gas exchange (O2 and CO2), determining REE (resting energy expenditure), nearly equal to BMR. Relatively inexpensive but depends on metabolic rate being at a steady state and confined to a metabolic cart.
- Doubly Labeled Water: A gold standard for measuring free-living total energy expenditure. Involves giving subjects "tagged" water, and collecting excretion of isotopes in saliva and urine. Expensive.
Adjusting Energy For Weight Change
- Weight loss composition is not all fat.
- Calorie restriction and exercise affect fat mass and fat-free mass composition differently.
- Greater adiposity = larger expected weight loss for the same change in energy intake.
Is There a Set Calorie Restriction Rule for Weight Loss?
- 3500 kcal/week for 1 lb weight loss is an often cited rule of thumb but is unrealistic.
- Weight loss occurs more gradually than assumed and is influenced by physiological variations over time.
Mathematical Simulation Models For Weight Change
- The body needs time to adjust to changes.
- Mathematical models account for the dynamic nature of weight change.
- Factors such as initial weight, weight composition, and metabolic adaptations are considered to provide more accurate estimations for calorie requirements.
Acceptable Macronutrient Distribution Ranges
- Fat: 20-35% of calories
- ** Carbohydrate:** 45-65% of calories
- ** Protein:** 10-35% of calories
- Specific recommendations (in kcal and grams) for a 2000 kcal daily diet are provided.
Summary
- With aging, physiological variables decline.
- Energy expenditure is the sum of BMR, TEF, and physical activity.
- Several methods exist to estimate energy expenditure.
- Energy needs must be adjusted if planning weight loss.
- Mathematical models offer more effective estimations of calorie requirements accounting for dynamic weight loss.
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Description
Explore the physiological changes in adults and how they impact energy needs and expenditure. This quiz discusses methodologies for determining energy needs and adjusting them for weight loss, while highlighting nutritional factors that influence diseases like cancer and heart disease.
