Dietary Protein Requirements Of Athletes Flashcards
How many amino acids are required for protein synthesis and how many are essential for adults?
Females: 0.75/kg/day
Males: 0.84 /kg/day.
Around 1 g/kg/day good enough for 98% populations.
Athletes: bottom line 1.2-1.7 g/kg/day. Upper limit: 2g/kg/day, but many athletes consume more than this. (No significant impacts after a certain limit i.e. a ceiling effect)
Which are the branched chain amino acids?
The essential amino acids. E.g leucine and valine.
Under what conditions would you expect protein/ amino acids to provide more fuel during exercise?
If carbohydrate availability is low, or ATP and ADP running low when duration of exercise is significantly long and towards the end for example a marathon.
Understand the effects of endurance and resistance training on protein metabolism?
Endurance training: during a competition e.g a marathon, amino acid metabolism will increase to 20-25% from 8% at rest, preferentially unbranched amino acids oxidized first then the branched. controlled by glutamate dehydrogenase. Through many training sessions involving endurance exercises, we become better fat burners i.e. our body reduces in metabolism of amino acids, and instead derive more energy from fat and glycogen i.e. glycogen sparing mechanism.
Resistance training: increases protein breakdown and synthesis rate. But synthesis is way longer than breakdown, so if consumption of protein at the time of RT with correct amount i.e. around 20 g maximum. Does not alter our ability to use protein as energy source i.e. 3-6%
Describe and explain the interplay between carbohydrates, proteins and energy intake for lean mass gain?
Many athletes over-consume proteins with a belief more is better for conservation and gain of lean muscle mass. At the same time, due to various reasons (sports where leanness is preferred like dance, anorexia nervosa, disorganization, accessibility issues etc) they do not consume enough carbohydrates and energy intake is lower than their requirements. This will not help them gain or preserve muscles, as sufficient calorie and carbohydrates are crucial. Proteins only have to be between the range of 1.2-1.7 g/kg/day for athletes across all types. Also, too much protein can lead to acceleration of renal diseases, can increase calcium excretion in urine and may be carcinogenic. Moreover, too little carbohydrate could lead to increased amino acid oxidation, which breaks down muscles.
Explain the recent research regarding the potential “protein window” pre and post exercise.
Protein consumption just pre and post exercise leads to greater muscle mass gain and strength gain due to increased protein synthesis rate, as opposed to consuming protein long before and after an exercise bout.
Outline recommended strategies for assisting athletes to gain lean body mass?
- Consume enough calories, including carbohydrate.
- Get organized to take protein in separate meals throughout the day.
- Consume pre and post an exercise bout.
- Max consumption per meal should be between 10-20 g of protein.
- Whey protein is good, but should not consume over 20 g due to ceiling effect.
- High quality protein like lean meats and dairy.
- Consume with 1g/kg carbohydrate snack.
- Don’t train on empty stomach.
- Right training program. (Stimulate muscle growth by damaging it first)
Understand how nitrogen balance is measure and calculated?
Nitrogen balance is an indicator of protein availability. (Amino group of amino acids)
Equal to nitrogen intake minus the sum of nitrogen loss in urine, faeces and dermal.
Understand the changes in protein requirements for novice compared to well trained endurance and resistance trained athletes?
Because the novice will have bigger rate of breakdown and synthesis after a bout of resistance training.
Understand the differences between whey and casein proteins in milk with respect to insulin and promoting lean mass gain?
In milk there is 80% casein and 20% whey. This improves muscle gain more than soy milk that contains little whey.
Whey protein contains the highest amount of branched amino acids that can effectively stimulate muscle protein synthesis pathways after exercise. I.e. “leucine trigger”.
