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