L3 energy balance


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L3 energy balance

  1. 1. Usable power Derived from stored chemical energy in foods we eat Allows people to: power bodies produce heat
  2. 2. Energy balance: • relationship between energy intake and energy used by the body • Energy expenditure: • energy used by the body
  3. 3. Measurement of chemical form of energy in foods Amount of energy needed to raise temperature of 1,000 g of water by 1º C Mistakenly called calories Bomb calorimeter measures kilocalories Kilojoule: Amount of energy needed to move 1 kg with an acceleration of 1 meter per second
  4. 4. Metabolism of carbohydrate, protein, fat, and alcohol End products of carbohydrate, protein, and fat metabolism: carbon dioxide water energy in the form of ATP End products of alcohol metabolism: some of the same by-products long-chain fatty acids
  5. 5. Simple calculations based on basic knowledge Scientific databases contain analyses based on: laboratory studies manufacturer information Availability and use of software programs based on these databases
  6. 6. Comprised of several components Unique for each person Measured indirectly or calculated using equations Total energy expenditure: processes in the body physical activity
  7. 7. Energy required for vital functions in body at rest Basal energy expenditure: expression of basal metabolism as kcalories over 24 hours different from resting energy expenditure heavier individuals have higher resting metabolic needs gender differences due to muscle mass and organ size debates on relationship to age
  8. 8. Energy expended for body temperature regulation varies based on surface area to weight ratio thermoregulation challenges alter energy use adjust energy expenditure calculations when thermoregulation issues occur impact of extreme ambient temperatures with normal conditions, little change Increased needs with infancy, childhood, adolescence, pregnancy, and lactation
  9. 9. A person’s metabolic rate is dependent on many things, including physical activity and the amount of muscle.” The metabolic rate is influenced by the activity level, the amount of muscle mass, and body temperature, among other things. Muscle and organ tissue is more metabolically active than fat, so if the person who is overweight has more fat mass, the basal metabolic rate may be slower than someone of the same weight who has more muscle mass.
  10. 10. However, people will not become overweight if they have high metabolic rate. Increasing physical activity will help develop more muscle mass, which is more metabolically active. No two individuals will have exactly the same metabolic rate.
  11. 11. Metabolic cost of digestion, metabolism, and storage of nutrients Typically 10% of every value of the food Protein thermic effect: 20 to 30% Alcohol thermic effect: up to 13% Fat thermic effect: less than 5%
  12. 12. Thermogenesis Physical component of energy expenditure actual exercise nonexercise activity NEAT: any activity involving muscle contraction activities of daily living Energy expended depends on activity intensity and duration
  13. 13. • Usually expressed as a ratio or percentage of basal energy expenditure • Laboratory measurements: –calculate kcalories used per minute of activity for various body weights –heavier person expends more energy in same activity than a lighter person
  14. 14. Predictive equations: estimate energy intake equations based on height, weight, gender, and age high margin of error based on healthy, normal weight individuals altering equations leads to more inaccuracies no established equation for older population
  15. 15. Relationship between energy intake and energy expenditure Balance fosters weight maintenance Negative energy balance: insufficient energy to support needs causes: insufficient intake and/or increased expenditure Positive energy balance: energy intake exceeds needs causes: increased intake and/or decreased expenditure
  16. 16. Individual differences Influence of biology and other factors on appetite, satiety, and metabolism
  17. 17. Low levels of activity prevalent Increased intake widespread Goals of national recommendations: reduce obesity provide adequate energy Estimated Energy Requirements: recommendations for population groups role of registered dietitian no advice supporting weight loss/weight gain
  18. 18. Excess energy consumption compared to needs Interventions when weight gain increases disease risk Target energy consumption or expenditure contributing to imbalance
  19. 19. Nurse’s role in intervention: explore sources of kcalories and “empty” calories brainstorm ways to create deficit find opportunities for physical activity Socioeconomic levels tied to positive energy balance Importance of education
  20. 20. A positive energy balance results from caloric intake exceeding energy expenditure, ultimately leading to weight gain. Children who do not engage in much physical activity tend to have a higher weight than those who are active. Impaired glucose tolerance may result when there is excess weight but it tends to develop over a period of years.
  21. 21. Result of insufficient energy consumption and/or excess physical activity Intervention necessary when health risks increase Target aspects of consumption or expenditure contributing to imbalance Team approach Nutrition assessment Assessment of physical activity levels
  22. 22. Elevation of metabolic response Avoidance of predictive equations Use of indirect calorimetry or modified approach