Quote:
Originally posted by fridayeyes
Oh, yeah - you may hear or read that the body can't assimilate more than 30g of protein at once, and that you will be 'wasting' anything beyond that if you eat it at one sitting. It's not true, so don't worry about it. Nat has the references if you want me to dig them up.
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Nat, could you please?
I think that this 30-g (or whatever) quantity of protein is a datum that's interpreted and misinterpreted depending on what the interpreting person wants you to believe.
If I am not mistaken, this number came from nitrogen retention studies. Then we have to consider whether they were looking at active or inactive persons and what diet they were eating. Lyle made a very good case in his book showing that protein requirements are inversely related to the amount of carbohydrates one is eating - less carbs, more protein required, and vice versa. If those studies were done on persons eating a carb-containing non-ketogenic diet (as I'm nearly certain they were because hardly anyone studies ketogenic diets), then this number is moot for our CKD- and LC dieting purposes.
Activity obviously matters in both quantity and quality. Cardio-only exercise does not promote muscle growth/remodeling to a significant degree. Weight training clearly does.
I've gotten more concerned with that number because even though nitrogen retention may be showing that all 30, 60, 90, 120, or however much protein is used, this does not mean that it's not used to produce glucose as well, which would prevent ketosis. I have a damn hard time getting into ketosis (might have to do with low bf), and recently I've split my meals so that each contains only 40 grams or so. It wasn't a strictly controlled experiment but seems like I cut 1/2-1 days from the time it takes me to get there. Once I am there, it seems not to matter as much. I've tested this and found that after 4-5 days of eating keto and working out, I can eat 150 grams of protein in a sitting and ketones go up. So technically on Fridays I can skip the mayonnaise and have a big tuna party; I pass on the fun though.
Anyways, just rambling...
I've never really figured out the glutamine deal. It's glucogenic (i.e., can be converted to glucose), causes more insulin release than other amino acids do, and is used by the body as a nitrogen carrier. All that could contribute to getting kicked out of ketosis but exactly how much glutamine are we talking here? Even if you eat an ounce of glutamine, that's only an ounce of glucose that can be produced, and it takes time to do so there would not be a big spike. Maybe there's a study on insulin spike after glutamine ingestion?