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  1. 1. Energy Intake and Expenditure Outcome 3
  2. 2. Kcals of energy for macronutrients <ul><li>1g Carbohydrates = 4kcals of energy </li></ul><ul><li>1g Protein = 4Kcals of energy </li></ul><ul><li>1g Fat = 9kcals of energy </li></ul>
  3. 3. Estimating Energy Requirements <ul><li>BMR (Basal Metabolic Rate) – this is the minimal calorie requirement needed to sustain life in a resting individual </li></ul><ul><li>You would burn this amount of energy if you slept all day or rested in bed for 24 hours </li></ul><ul><li>A number of factors can affect BMR </li></ul><ul><li>Some factors speed your BMR up so you are burning more calories per day to stay alive </li></ul><ul><li>Others slow your metabolism down so you need to eat fewer calories to stay alive </li></ul><ul><li>Make a list of what you think the different factors are, giving reasons. </li></ul>
  4. 4. Factors affecting BMR <ul><li>Age </li></ul><ul><li>Body size </li></ul><ul><li>Growth </li></ul><ul><li>Body Composition </li></ul><ul><li>Fever </li></ul><ul><li>Stress </li></ul><ul><li>Environmental temperature </li></ul><ul><li>Fasting </li></ul><ul><li>Thyroxin </li></ul>
  5. 5. Estimating energy and macronutrient requirements <ul><li>To estimate energy requirements you need to calculate your Basal Metabolic Requirements (BMR) </li></ul><ul><li>This is measured in kilocalories per day </li></ul><ul><li>for a 10-17yr old male BMR = 17.7W(weight in Kg’s) + 657 </li></ul>
  6. 6. BMR <ul><li>Males 10-17yrs BMR=17.7W+657 </li></ul><ul><ul><ul><ul><ul><li>18-29yrs BMR=15.1W=692 </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>30-59yrs BMR=11.5W+873 </li></ul></ul></ul></ul></ul><ul><li>Females </li></ul><ul><ul><ul><ul><ul><li>10-17yrs BMR=13.4W+692 </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>18-29yrs BMR=14.8W+487 </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>30-59yrs BMR= 8.3W+846 </li></ul></ul></ul></ul></ul>
  7. 7. Estimating energy and macronutrient requirements <ul><li>You also need to consider your level of physical activity and training </li></ul><ul><li>Simplest method of estimating your total energy requirements: </li></ul><ul><li>Multiplying BMR by PAL (physical activity level) </li></ul>
  8. 8. PAL <ul><li>To calculate PAL you have to make assumptions about the energy demands of your occupational and non-occupational activity levels </li></ul>
  9. 9. Pal for three levels each of occupational and non-occupational activity 1.7 1.9 1.7 1.8 1.6 1.6 Very active 1.6 1.8 1.6 1.7 1.5 1.5 Moderately active 1.5 1.7 1.5 1.6 1.4 1.4 Non-active F M F M F M Heavy Moderate Light Non-occupational activity Occupational Activity
  10. 10. Alcohol <ul><li>Concentrated source of energy </li></ul><ul><li>Produces 7kilocalories per gram </li></ul><ul><li>This energy is not available to the working muscles </li></ul><ul><li>Excess energy from alcohol is stored as fat </li></ul><ul><li>Current safe limits recommended by Health Education Authority – 3-4 units/day for men, up to 2-3 units /day for women </li></ul>
  11. 11. Energy needs and energy balance <ul><li>Energy balance is when the amount of energy taken in = the amount of energy used (output) </li></ul><ul><li>4 major components to energy output </li></ul><ul><ul><ul><li>Resting metabolic rate </li></ul></ul></ul><ul><ul><ul><li>Dietary thermogenesis </li></ul></ul></ul><ul><ul><ul><li>Physical activity </li></ul></ul></ul><ul><ul><ul><li>Adaptive thermogenesis </li></ul></ul></ul>
  12. 12. Energy needs and energy balance <ul><li>Basal Metabolic Rate (BMR) account for 60-75% of total energy output </li></ul><ul><li>BMR will depend on body composition e.g. gains in muscle mass will increase BMR </li></ul><ul><li>Sex, age and genetic background also have a bearing </li></ul><ul><li>Dieting (low energy intake) can lead to a reduced BMR </li></ul>
  13. 13. Energy needs and energy balance <ul><li>Dietary Thermogenesis (DT) – energy expended above BMR – digestion, absorption, transportation and storage of food </li></ul><ul><li>Influenced by calorie content and composition of meals eaten </li></ul><ul><li>High energy intake and regular eating pattern help maintain higher rates of DT </li></ul>
  14. 14. Energy needs and energy balance <ul><li>Physical Activity (PA) – most variable component of energy expenditure </li></ul><ul><li>This is additional expenditure above BMR and DT </li></ul><ul><li>How much will depend on level of activity, lifestyle, how often and how energetically and for how long we participate in sport and exercise </li></ul>
  15. 15. Energy needs and energy balance <ul><li>Adaptive Thermogenesis (AT) is energy expenditure due to environmental or physiological stresses placed on the body </li></ul><ul><li>Changes in temperature - shivering </li></ul><ul><li>Stress that causes anxiety or fidgeting </li></ul>
  16. 16. Energy needs and energy balance <ul><li>When energy intake is greater than output </li></ul><ul><li>this is known as </li></ul><ul><li>Positive Energy Balance – </li></ul><ul><ul><ul><ul><li>Weight is gained </li></ul></ul></ul></ul><ul><li>When energy intake is less than output, we </li></ul><ul><li>use up fat stores, this is known as </li></ul><ul><li>Negative Energy Balance </li></ul><ul><ul><ul><ul><li>Weight is lost </li></ul></ul></ul></ul>
  17. 17. Energy needs and energy balance <ul><li>Sportspeople are concerned about maintaining or attaining an optimal body weight </li></ul><ul><li>Some sports set weight restrictions e.g. </li></ul><ul><ul><li>Body building </li></ul></ul><ul><ul><li>Boxing </li></ul></ul><ul><ul><li>Horse racing </li></ul></ul><ul><ul><li>Martial arts </li></ul></ul><ul><ul><li>Rowing </li></ul></ul>
  18. 18. Energy needs and energy balance <ul><li>Some sports benefit from increased body size e.g. rugby or American football </li></ul><ul><li>Other sports need a low body weight which may be below natural weight – weight-controlled sports e.g. </li></ul><ul><ul><ul><li>Distance running </li></ul></ul></ul><ul><ul><ul><li>Gymnastics </li></ul></ul></ul><ul><ul><ul><li>Diving </li></ul></ul></ul>
  19. 19. Energy needs and energy balance <ul><li>To maintain a low body weight or reduce weight whilst also maintaining a nutritionally suitable diet inappropriate weight loss practices can be found e.g. </li></ul><ul><ul><li>Fasting </li></ul></ul><ul><ul><li>Skipping meals </li></ul></ul><ul><ul><li>Laxative abuse </li></ul></ul><ul><ul><li>Binging </li></ul></ul><ul><ul><li>Purging </li></ul></ul><ul><ul><li>Intentional dehydration – use of sweat-suits or saunas </li></ul></ul>