10 21 13 kin 110 class notes PRO as an energy source Protein most misunderstood concept in sport nutrition o Athletes overemphasize the importance of protein o Or o Underemphasize it and think its less important than it really is Protein marketed as both food and diet Popularity of PRO supplements o 1 Main component of muscle true o 2 Important for energy production true but mostly not true o 3 People don t eat enough not true o 4 Needs for athletes much higher than for non athletse does it matter how much other energy Does it matter what types of exercise you are doing Differences between PRO in food and as supplements o Supplements purified so other components are removed o CHO fat vitamins minerals o Protein supplements are not the same All PRO is functional structural enzymes transporters immune system o PRO deficiencies more serious Major PRO sources o Animal products o Some plant products Tofu Energy value for PRO o Total energy 5 25 kcal gram o But 1 PRO only 92 94 digestible especially plants pros Lose 40 kcal gram so digestible energy 4 85 kcal gram 2 Energy in the nitrogen group cannot be broken down by human enzymes metabolized o 85 kcal g nitrogen o 4 0 kcal g for PRO correcting for digestibility and metabolism 4 0 kcal g in PRO essential amino acids have to be part of diet about 9 20 amino acids o non essential amino acids can be synthesized from other amino acids PRO from other animal sources complete amino acid ratio similar to human needs o Plant PRO incomplete 1 essential o Ratio low compared to human needs Beans low in methionine Corn rice low in lysine Problem of incomplete PRO for vegans vegetarians Incomplete proteins complete proteins Tofu rice Need to understand use of PRO for energy during exercise and how important is it o Which athletes need more protein and why How much PRO is used during exercise Is it affected by intensity or duration How to dietary PRO needs change with total energy needs 1800 leibig PRO supplies all energy for exercise o 1840 s smith measures N2 and CO2 excretion of prisoners 2 german researchers challenge idea that PRO alone powers exercise
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