The question says it all. What's the deal with nutrient absorption at a meal? I am really only eating 3 meals a day and they aren't exactly square. The meat feast happens after a long day of hunting.
For dinner tonight I ate two chicken legs with skin on them. That's two thighs and two drumsticks for those counting at home. Less the bones, the meal came out to about 14 oz of chicken consumed in one sitting. A delicious endeavor, but one I wonder might have been extended over to smaller meals. I felt fine afterwards and I had just done some heavy lifting at the gym.
I've heard that the body can only absorb so much protein at one time. But I've also heard that complex real foods like meat take time to break down, digest and be absorbed. So where you might not be able to take in 100 grams of protein from a whey shake, that same amount of protein which I consumed during my chicken feast might actually be used up properly in my body. I am trying to get a gram per pound for my paleo self and I am finding that two legs of chicken or a nice new york strip eaten in one sitting helps get me there. But I'd like to know peoples thoughts, theories, research on high protein consumption at each meal.
asked byMikeD (3641)
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on September 10, 2010
at 05:20 PM
Layne Norton, bodybuilder, studied amino acid uptake for his PhD thesis. He says don't worry about max absorption:
"If our digestive systems didn???t absorb most of what we eat than anytime you had a big meal you would have diarrhea like clockwork from the undigested material in the gut! It also makes very little sense from an evolutionary standpoint to be very wasteful with nutrients when primitive man may have only been able to eat one large meal in a day at times. Our species would not have survived very long if we were wasteful with nutrients and did not absorb amino acids beyond a certain level. In reality, the body has an extremely high capacity for amino acid absorption. What these people who spout this nonsense are really referring to is amino acid utilization. You see, even if we absorb 100% of the amino acids we ingest, that doesn???t mean they will all reach the skeletal muscle and input towards building muscle mass. In actuality a very small percentage are used for that role. The cells of the small intestine and liver extract a huge amount of amino acids for energy and their own synthesis of new proteins in first pass metabolism before they ever reach the bloodstream! Once in the bloodstream amino acids can also be taken up and utilized by other tissues such as the kidneys, heart, skin, etc. So it is not a question of how much protein/amino acids can be absorbed at a meal, rather the question is what level of protein at a meal gives the maximum benefit for muscle building?"
on September 08, 2010
at 02:23 PM
Ok, I will get the ball rolling. I think I cam up with the idea from Cordain when he said on page 67 of the Paleo Diet that if you exceed 35% of your daily caloric intake from protein for an extended period of time your body will protest with nausea, diarrhea, abrupt weight loss and other symptoms of protein toxicity.
He also says its impossible to overeat pure protein.
Then on page 101 he talks about 'rabbit starvation' wherein a person consuming large quanities of lean meats taxes their liver which can't eliminate all the nitrogen. The upper limit for most people is described as 200-300 grams per day or 30 to 40 percent of ones daily calories.
Vilhjalmur Stefansson from Wikipedia:
The groups that depend on the blubber animals are the most fortunate in the hunting way of life, for they never suffer from fat-hunger. This trouble is worst, so far as North America is concerned, among those forest Indians who depend at times on rabbits, the leanest animal in the North, and who develop the extreme fat-hunger known as rabbit-starvation. Rabbit eaters, if they have no fat from another source???beaver, moose, fish???will develop diarrhoea in about a week, with headache, lassitude and vague discomfort. If there are enough rabbits, the people eat till their stomachs are distended; but no matter how much they eat they feel unsatisfied. Some think a man will die sooner if he eats continually of fat-free meat than if he eats nothing, but this is a belief on which sufficient evidence for a decision has not been gathered in the North. Deaths from rabbit-starvation, or from the eating of other skinny meat, are rare; for everyone understands the principle, and any possible preventive steps are naturally taken."
Of course none of this really answers the question of absorption during a meal but maybe the answer is that with a complex mix of fat and protein being consumed together your body will absorb the meal just fine. If over the coarse of a few days you consume too much lean proteins and not enough fats your suffer from malabsorption and toxicity but that probably isn't a problem for a paleo eating the majority of his/her calories in fat.
on September 08, 2010
at 08:27 PM
How long is a peice of string?
There isn't really a good answer to your qustion. A large number of different factors probably influence the rate of absorption.
If you want an interesting read on the subjest try this article: A Review of Issues of Dietary Protein Intake in Humans. The article mentions evolution, hunter-gatherer diets and even Vilhjalmur Stefansson. There seems to be very little research on the subject of protein absorption with real foods.
The best estimate seems to be that you can absorb about 1-4 grams of protein per hour from a meal of real food.
I would guess that you can absorb most of the protein you can comfortably eat in a meal of real foods if you are not stuffing yourself. You never absorb all of the protein you eat from any type of food, digestion isn't 100% efficient.
on September 10, 2010
at 04:46 PM
Great question, I've been wondering about for a while. I remember reading somewhere (maybe even on this forum) that the body can absorb only 30g of protein in one meal, whatever is above that goes straight into fuel or body fat. I wouldn't worry much about it all if I didn't have to still loose some weight. I know many people like the big, once a day meal with all the protein at once.
But for people who need to keep the body fat at least in check if not lower it - is it better to spread the protein throughout the day or is there no difference whatsoever?