Fat was also crucial to our survival because humans can only derive between 35 to 50 percent of our energy from proteins. Any surplus protein beyond that poisons us, so the rest of our calories must come from fats or carbohydrates.
Excess protein poisons us?
But they were carnivores? This makes no sense to me.
Yes, indeed. Excess protein overwhelms the uric acid cycle and leads to ammonia toxicity. The body has a limited capacity to store amino acids, so the excess get deaminated and the ammonia thus released needs to be dealt with. Some of it can be turned into nitric oxide and used to regulate blood pressure. But the body isn’t designed for us to eat too much protein, so too much ammonia can build up and be toxic.
Protein is needed for structural purposes; it is a much less efficient source of energy than fatty acids and glucose. So you don’t want to try to live on protein alone. Hence the need for fat for energy.
yea with the wording it does sound weirdo kinda but think ‘rabbit starvation’ in that if you eat only super lean meats and very very little fat you will go out of balance and I guess, hence the word poisoning comes into effect for the process that goes down. What Paul said too LOL
Don’t tell Shawn Baker this. That guy eats 3 steaks – for breakfast.
Personally, I think “rabbit starvation” is not scientific and has never been shown to be true. I think it’s scientifically unsound.
For instance, here’s Wikipedia’s entry:
Take a look at the references. There are no RCTs of people actually trying to eat “too much” protein. It’s all smoke and mirrors.
If I eat lower fat beef, I can easily – easily – eat 250+ grams of protein per day. Yet I can only get 45% of my calories from that? Where are all the other calories coming from?
Moreover, Dave Feldman asked for people who have kept carbs less than 20g/day while eating a high P:E diet. By definition, that will be high protein. Tons of people said they were able to do this. Some for years, even decades.
Are they all dying due to too much protein, not enough fat? It doesn’t appear so.
Until I actually see tests on humans, I think this “rabbit starvation” theory is unproven. I think it’s a myth, in fact.
Does this mean I think you SHOULD eat nothing but protein? No, I think some amount of fat helps too.
on the show Alone or other survival shows tell real fast that only super low fat protein will not sustain energy in a person for too long, especially with real life interaction, like hunting for your food on your plate :), it can’t give us long term survival. Thing is it has to be long term. One gal existed on hares for a long time and was dying to catch a ‘fatty fish’ for fat cause she was going down hill fast just eating a bunny a day kinda so…yea it is real. Thing is you gotta try it HAHA and thru real experience does one find out real truths on things ya know.
We can’t even put apples to apples ever about ‘real rabbit starvation’ against any of us truly. You have to do it to know it. Plus real science like Paul said
The body can metabolise protein when necessary, but it comes at a greater metabolic cost. In other words, it takes more energy to metabolise amino acids, because they first have to be deaminated, converted into glucose or a fatty acid, then metabolised. So the net yield of ATP is lower. If it starts with glucose or fatty acids directly, it doesn’t need to spend energy on those first two steps, so under normal circumstances, the body avoids metabolising protein, saving the amino acids for structural purposes.
Again, to clarify, there are two issues here:
Rabbit starvation: Part of the problem with not getting enough fat is not simply the lack of energy, but the absence of essential fatty acids. Remember that, while we don’t need much, we must have some ω-3 and ω-6 fatty acids in our diet, or we will sicken and die. This despite the fact that an excess of ω-6 fatty acids is not good for us. (It’s like insulin: necessary for life, but too much isn’t good, either.)
"Protein toxicity": As I mentioned in my earlier post, the body can store only a small amount of amino acids in what is called the “labile pool.” Any excess of amino acids beyond that must somehow be disposed of. The usual method is to deaminate (i.e., remove the ammonia from) the excess amino acids, convert the ammonia into uric acid, and excrete it in the urine. A protein intake of about 3.3 grams per kilogram of lean body mass a day is enough to start overwhelming most people’s uric acid cycles, leading to a toxic buildup of ammonia from an inability to clear the excess nitrogen.
I am seeing some confusion in people’s posts here, and it appears to be the result of not thinking things through to their proper conclusions. Nothing I’ve posted in this thread is new information.
The point people may not be remembering here is that what distinguishes an amino acid from a carbohydrate or a fatty acid is the presence of at least one amino group (NH2). Carbohydrates and fatty acids are made exclusively of carbon ( C ), oxygen ( O ), and hydrogen ( H ), with no nitrogen ( N ). The presence of the nitrogen means that amino acids must be handled differently in the human body. Again, this is all basic organic chemistry.
Fat is essential, it’s no secret. A pure protein diet truly makes people sick. (When life is extremely tough and people eat other people who died of starvation, they better crack the bones to get some fat too or else they keep starving even getting theoretically enough energy of the super lean meat).
But it’s quite extreme not eating enough fat especially if we don’t eat much carbs either.
About the “too much protein” even in the presence of fat, I know little. I saw numbers and I know some people are more sensitive and need low-ish protein… But it’s really a problem for a normal person. I can’t eat too much protein (or too little) even if I try.
yea rabbit starvation is a very simplistic view of it all obvy.
but it leads one to figure it out. FAT IS A MUST and that is why anyone not ingesting enough fat intake vs. ‘any other food be it veg or super low fat protein’ is gonna have troubles ‘eventually’ and that is why SO many if they can’t balance or have med issues only to them and more they are battling, find tough roads ahead.
fatty meats. key to life
Super predator is e en putting it mildly.
Humans, with their big brains and ability to make and use weapons have evolved in something so dangerous that we are in the middle of the next mass extingtion.
Nature has produced some pretty scary animals like a t-rex but nothing as deadly as humans.
Reality is, want to find the real monster, dont look under the bed, look in the mirror.
So everyone jumped on “surplus protein poisons us…” As if the contention is that consuming a few grams of protein in excess of our essential needs is like eating arsenic. Everyone ignored “humans can only derive 35-50 percent of energy from proteins…” @PaulL explained why not: it takes more energy to extract energy from protein/amino acids than the energy derived from doing so. As the amount approaches 50% the net energy gain is zero.
So-called ‘rabbit starvation’ is just a colloquial term derived from North American indigenous peoples who understood that as the energy gain from eating falls, the metabolism consumes more and more endogenous ‘edibles’: fat, muscles, connective tissues, bones and eventually various internal organs. All the while eating as much rabbit as you can get. To no avail. One just starves to death with a full stomach.
Our Pleistocene and earlier ancestors were predominantly carnivorous, but that does not mean ‘protein only’. Shawn Baker’s steaks contain plenty of fat as well as protein. Our ancestors could be more properly described as ‘Fat Hunters’. That said, each of us is an ‘n=1’. ‘Adequate protein’ for one may well be inadequate protein or ‘too much’ for another. By ‘too much’ I don’t mean rabbit starvation level amounts, just more than can be utilized and gets excreted. If you have kidney problems, it makes a big difference in what’s ‘too much’ for you. Just my opinions.
I was JUST thinking of her when I read your comment. I always feel bad when they have to leave due to that and when the heck is a woman going to win??
This makes so much sense
“ …This means that after the human lineage diverged from the chimp line, around six million years ago, we progressively became more adapted at extracting energy from meat, and lost most of our ability to do so from plants.”
Hence my gluten intolerance, and developing dairy intolerance.
It does, doesn’t it.
I use to believe humans were facultative carnivores.
Nowadays i’m more and more leaning towards obligate carnivores.
Meaning without lots of meat and fat it is very hard to stay healthy for long.
We can survive on plants if we have to, but its at a big cost.