Protein 2 (wk 8) Flashcards
How much post-exercise protein?
-> Exercise conditions always produces superior rates of muscle protein synthesis (especially the combination of exercise with protein nutrition)
What is the optimal protein dose relative to body weight in young adults?
-> There is a plateau/ breakpoint at 0.24g/kg of protein (g) with bodyweight
What EEA’s are required to increase MPS after resistance exercise?
-> A series of studies in the US found that only the essential amino acids are required to increase muscle protein synthesis after resistance exercise. EAA’s are essential we get them from food intake because they are vital for the synthesis of all our internal tissues and organs, especially muscle.
Post-exercise milk consumption promotes greater MPS than soy protein?
-> To get a maximum response after exercise, you can consume the same amount of protein from whole food e.g. glass of milk, salmon and pork. It is not essential to have a supplement to maximise post-exercise rates of protein synthesis, however they are easy and convenient.
What is it in milk that makes it more effective for MPS?
-> Milk is composed of whey protein (20%) and casein (80%) protein fractions. Whey is viscous and translucent, while casein is curd-like and lumpy. The whey protein fraction in milk is rapidly digested, this is because the amino acids get into circulation very quickly and as the whey protein is comprised of short peptide chains, the acidic environment (the gastrointestinal tract and small intestine) is able to break it down very quickly. Casein is composed of more complex peptide chains and when casein hits the acidic environment of the stomach, it takes longer to break down because it clogs and takes a long time to break these down for them to be then released.
What is leucine?
-Leucine is thought to be an important trigger for muscle protein synthesis. Animal proteins contain more essential amino acids, particularly the branched chain amino acid of leucine.
Eating before you sleep?
-> One study got participants to ingest 40g of casein or a non-caloric placebo 30min prior to sleep (11:30pm) after performing a bout of resistance exercise in the evening (8pm). They were measured to see how much new protein had been synthesised by the muscle overnight in response to the placebo or 40g of casein. Breakdown, synthesis, oxidation and net balance was larger in the casein than placebo condition. The net balance was negative with the placebo condition and was positive with the casein ingestion.
Resistance exercise prolonging muscle anabolic sensitivity to protein provision:
-In the recovery phase after resistance exercise, the rates of muscle protein synthesis remain elevated for an extended period. If the volume of work performed in the resistance exercise session is high enough, there will be a pronounced increase in protein synthesis and will remain elevated above pre-workout levels for at least 24, possibly 48 hours – but depends on how hard you trained and how experienced you are with resistance training. When you consume protein in the post-exercise recovery window, there is an augmenting feeding response. This is where the exercise muscle has contracted and is more receptive and sensitive to the anabolic actions of the amino acids that you consumed in the dietary protein – allowing a larger response.
What type of weight is lost during energy deficit?
-> In persons with normal weight, the contribution of fat-free mass loss often exceeds 35% of total weight loss
How to overcome the blunting of protein synthesis during energy restriction:
-> Resistance exercise is important to maintain protein synthesis after/during exercise. Muscle mass was preserved during energy restricted diet through resistance exercise.
Can higher dietary protein promote high quality weight loss during the energy deficit?
-> In a study, was found that, 2.3g.kg or 35% energy from protein was superior to 1.0g/kg-1 or 15% energy from protein for maintenance of lean body mass during short-term hypo energetic weight loss. Lean mass loss was prevented in the group who consumed high protein.
Factors that can help lean mass preservation/ gain during energy restriction:
- Balanced distribution of daily protein intake (young: 20-25g of protein/meal, old 35-40g of protein/ meal)
- Early post-exercise protein intake (leucine-rich, rapidly digested source)
- Slow rate of weight loss (0.5kg/week)
- Higher protein diet (~1.2-2.3g.kg-1)
- High dairy protein consumption (3-7 served dairy/day)
- Exercise training (particularly resistance exercise)
