Energy Balance


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Energy Balance

  1. 1. Energy Balance Getting the Equation to Work
  2. 2. The Hard Question <ul><li>How much should I eat each day? </li></ul><ul><ul><li>What you are doing </li></ul></ul><ul><ul><li>Positive/negative or equal energy balance </li></ul></ul><ul><ul><li>Need to calculate BMR </li></ul></ul>
  3. 3. Each Person is an Individual <ul><li>Largest energy requirements for those who are: </li></ul><ul><ul><li>Young </li></ul></ul><ul><ul><li>Growing </li></ul></ul><ul><ul><li>Large </li></ul></ul><ul><ul><li>Muscular </li></ul></ul><ul><ul><li>Have long high intensity training sessions </li></ul></ul>Nutrition Applied PT571001; SP572001; SM569001
  4. 4. Energy Balance <ul><li>Total Daily Energy Intake: (TDEI) </li></ul><ul><ul><li>refers to the energy obtained from the diet in a day period </li></ul></ul><ul><li>Total Daily Energy Expenditure: (TDEE) </li></ul><ul><ul><li>refers to all the energy used to power the body through a day period </li></ul></ul><ul><li>Energy Balance when: </li></ul><ul><li>TDEI = TDEE </li></ul><ul><li>-> amount of energy put into body equals amount of energy spent over the day. </li></ul>
  5. 5. Energy Balance and Body Weight <ul><li>If TDEI = TDEE </li></ul><ul><ul><li>body weight (BW) remains stable </li></ul></ul><ul><li>If TDEI > TDEE </li></ul><ul><ul><li>POSITIVE energy balance </li></ul></ul><ul><ul><li>body stores extra energy (  BW) </li></ul></ul><ul><li>If TDEI < TDEE </li></ul><ul><ul><li>NEGATIVE energy balance </li></ul></ul><ul><ul><li>body uses stored energy to make up difference (  BW) </li></ul></ul>Changing energy balance affects body weight
  6. 6. How Do We Measure Energy Expenditure? <ul><li>Indirect Calorimetry </li></ul><ul><ul><li>Hard to do in the field </li></ul></ul><ul><ul><li>Measures RER by O 2 /CO 2 ratios </li></ul></ul><ul><ul><li>Reliant on knowing diet and exercise </li></ul></ul><ul><li>Doubly-labelled Water </li></ul><ul><ul><li>Accurate but very expensive </li></ul></ul><ul><li>Prediction Equations </li></ul>
  7. 7. Food Energy <ul><li>The macronutrients in food provide energy to power body functions. </li></ul><ul><li>Food energy measured in kilojoules (kJ) or kilocalories (kcal or Cal): 1Cal = 4.2kJ </li></ul><ul><li>What you eat is important because: </li></ul><ul><ul><li>Different energy kJ/g of each nutrient: </li></ul></ul><ul><ul><li>CHO = 16kJ/g Protein = 17kJ/g </li></ul></ul><ul><ul><li>Fat = 37kJ/g Alcohol = 29kJ/g </li></ul></ul><ul><ul><li>Nutrients used differently in the body </li></ul></ul>
  8. 8. Food Energy <ul><li>Alcohol in = Alcohol oxidation </li></ul><ul><li>Carbohydrate in = Carbohydrate oxidation </li></ul><ul><li>Fat in = Fat oxidation </li></ul><ul><li>Protein in = Protein oxidation </li></ul><ul><li>When any of the nutrients in are greater than the oxidation then have food energy stored. </li></ul>
  9. 9. Total Daily Energy Expenditure <ul><li>How do we change our TDEE? </li></ul><ul><ul><li>BMR </li></ul></ul><ul><ul><li>Physical Activity </li></ul></ul><ul><ul><li>Thermic Effect of Food </li></ul></ul>TEF Physical Activity Basal Metabolic Rate
  10. 10. What is TDEE <ul><li>The energy used to power the body through 24 hours </li></ul><ul><li>TDEE is made up to 3 parts: </li></ul><ul><ul><li>Basal Metabolic Rate (BMR) </li></ul></ul><ul><ul><ul><li>Energy required for basic body functions </li></ul></ul></ul><ul><ul><ul><li>50-60% TDEE </li></ul></ul></ul><ul><ul><li>Physical Activity </li></ul></ul><ul><ul><ul><li>Includes energy cost of purposeful activities of daily living and/or planned exercise </li></ul></ul></ul><ul><ul><ul><li>20-40% TDEE </li></ul></ul></ul><ul><ul><li>Thermic Effect of Food (TEF) </li></ul></ul><ul><ul><ul><li>Energy required to process food in the body </li></ul></ul></ul><ul><ul><ul><li><10% TDEE </li></ul></ul></ul>
  11. 11. Basal Metabolic Rate <ul><li>Basal metabolic rate influenced by: </li></ul><ul><ul><li>Body Size: BMR  with body mass </li></ul></ul><ul><ul><li>Body Composition: adipose (fat) tissue has lower energy demand than muscle </li></ul></ul><ul><ul><li>-> BMR  with  muscle;  with  fat. </li></ul></ul><ul><ul><li>Age: BMR  with age </li></ul></ul><ul><ul><li>Gender: BMR  women cf men (  total mass, women higher fat to muscle ratio) </li></ul></ul><ul><ul><li>Genetic component </li></ul></ul><ul><ul><li>Nutritional status: adaptive changes to modified energy intake </li></ul></ul>
  12. 12. Physical Activity <ul><li>Most variable component of energy expenditure. </li></ul><ul><li>Physical activity energy demand influenced by: </li></ul><ul><ul><li>Type (  with  weight bearing/loading) </li></ul></ul><ul><ul><li>Intensity (  with  intensity) </li></ul></ul><ul><ul><li>Duration (  with  duration) </li></ul></ul><ul><ul><li>Size of Individual (  with  size) </li></ul></ul><ul><ul><li>Rest between movements (  with  rest) </li></ul></ul><ul><ul><li>Skill of movement (muscle efficiency) (  with  skill) </li></ul></ul>
  13. 13. Factors Affecting TEF <ul><li>Genetically determined?? </li></ul><ul><li>Diet composition: </li></ul><ul><ul><li> TEF in response to protein cf fat and CHO </li></ul></ul><ul><li>Very small contributor to total daily energy expenditure </li></ul>