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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6893534/

This review debunks the "bioavailability" and "quality" claims quite easily.

"bioavailability" (pdcaas diaas) is a contrived measure of protein source completeness made up to characterize protein issues of starving humans. It was also calibrated on rats and pigs, not humans. The "complete protein" misinformation is everywhere. Even on Wikipedia https://en.wikipedia.org/wiki/Complete_protein (edit: now I see that someone recently changed the statement to "adequate proportion" while previously it was just referencing that it contains all 9 essential amino acids).

All plants contain all essential amino acids, including green grass. Completeness in case of no starvation does not mean a thing. If you are eating 3000kcal of wheat every day, protein is no longer a worry, despite wheat having a 25% made-up bioavailability measure that was deduced by checking what happens to nitrogen in a live pig.

The protein "concentration" is just not true. Chicken breast does not have 90g of protein in 100g of chicken breast. 35g of protein in 100g of raw soybean. You will have to find a really rare steak of 100g to top that.

> Many ex-vegans have been consistently anemic, even while taking iron supplements, until they re-introduced meat.

This is not at all the conclusion of peer reviewed articles. Increased occurrence of nutrient deficiencies in vegan populations does not exist. Some people get deficiencies on any diet, and this is also the case for diets that have low-calorie high-volume foods like plants. Nothing special about that. People need to eat more volume but rarely do so. Similarly, they need to eat more calories. Talking about micronutrients in a world with no starvation is unnecessary. If you're eating a variety of plants, enough calories, it is certain you are consuming all of the necessary nutrients and protein. If you want to do powerlifting, marathon running, you will need to adjust your diet, whatever diet it is.

I think you misunderstood the protein concentration concerns. People are concerned about the ratio of calories from protein to calories from other macronutrients. In the case of beans like edamame, the concentration of fiber becomes relevant as well.

In contrast, chicken breast is nearly entirely calories from protein and very low fiber. Replacing some chicken breast with soy makes sense, but your fiber budget would cap out quickly and that would leave no room for other fiber rich foods like fruits and leafy green vegetables.

There was an explicit mention of protein quality and bioavailability. Both terms are standard and widely used. If OP meant something different by these terms, then fine. There's a minor loss of protein that is trapped in fibre for most plant foods that humans eat.

There is small amount of fiber in tofu, seitan, tempeh or other soy derivatives.

The "protein concentration" was mentioned together with iron, as if it is a problem of deficiency, not in the context of obsessive compulsive dieting by tweaking your macros to achieve the best results.

I am not sure the fiber budget you mention is a reality. There is no threshold where your body will stop behaving if you consume too much fiber.

Some people have significant health problems if they eat to much fiber. They are literally on a low fiber diet as a medical matter.

The rest of us have lower GI problems of some sort if we go too much over the daily recommended amount. That can cause significant practical and social problems. But you are correct that we probably won't die. It could be painful in some cases, though, and that would be enough.

I'm one of those people who genuinely function better with a high-meat diet.

The irony being that I absolutely love veggies of all kinds, and would have no trouble eating vegetarian, if it weren't for the side effects on my health. I'd be thrilled to try lab meat!

Why does a food need to contain 90% or 100% protein? I think many people vastly overestimate how much protein they need.

It's not true that by weight chicken breast has higher concentration of protein than beans.

100g of raw beans, or 100g of raw lentils, has more grams of protein than a chicken breast. 100g of raw soybeans has more grams of protein than same amount of beef.

Of course, "raw" is the catch word, because when cooked, beans/lentils fill with water and then you might claim that concentration has been lowered but the amount of protein stays the same (nothing is lost by cooking).

Protein:Fat+Carb ratio is what matters when talking about protein concentration.

Define "need." Sure, I could live off bread and water, but if I want optimal function, I have found that a high protein diet is the silver bullet.

Once you discovered that a high protein diet worked for you, how many other diets/options did you try?

I'm a greybeard so I've had lots of time to try different diet+exercise programs. I was a serious cyclist for a couple decades and during that time, I tied high carb, vegetarian and the 40/30/30 diet that was trendy back in the 90s. Despite being much younger and burning a large # of calories, I still had persistent belly fat, which I attribute to the large # of carbs I inhaled on the bike. 40/30/30 worked better all around though. When I started lifting I went to .8grams of protein per LB of bodyweight and haven't felt the need to try anything else.

I know a lot of people who have had success maintaining fitness goals on a high protein diet, including people who struggle with obesity.

I'd say that latter case especially counts as a need.

>Meat has a much higher concentration of protein and iron than vegan food.

Exactly this. The whole point is the Protein:Fat+Carb ratio and vegan options just don't come close. My diet has me eating ~150 grams of protein a day. If I were vegan, I'd be consuming an insane amount of carbs and/or fat along with that protein. My high protein diet combined with weight lifting is the only thing that keeps the dad bod at bay.

My diet is roughly 40% protein, 35% fat, 25% carbs. It’s extremely high in protein as I’m on a 20% calorie deficit, aiming for at least 1.2g protein per lb lean body weight, 35% fat preferring it to carbs and making up the remaining calories with carbs. I prefer fat over carbs as my body hangs on to carbs and doing a metabolic test was told I would be better with higher fat to carb ratio based on my stats and goal of getting leaner while maintaining muscle.

I’ve been planning meals using linear programming with the Simplex algorithm (https://en.wikipedia.org/wiki/Simplex_algorithm) to calculate the optimal ingredients/quantities to hit my macro goals while minimising total calories.

From playing about it’s impossible for me to hit my macro goals using a pure vegan/vegetarian whole food diet. To hit my protein goals my carb ratio would need to go way up and I’d then need to lower the fat percentage and even then I’d likely be in a caloric surplus. I could lower the protein proportion to try and hit the total calorie goal but then I’d likely be in a catabolic state and loose muscle mass.

I really wanted to eat less meat just for the fact meat costs more and as a plus eating less lowers my environmental impact. When plugging in the numbers with simplex it becomes very apparent it’s extremely hard to get the nutritional bang for your buck you get from meat. For the average person not interested in strength training or body fat percentage it’s probably not as big a deal but the fact remains it’s extremely hard to get specific macro targets without meat.

I did competitive powerlifting for a while and am still an avid stength trainer. I didn't go full vegan, but my wife did, and there for a time my diet mostly aligned to hers because she was doing the shopping while I was working. Overtime I started to get a lot of minor injuries out of nowhere. I tried doing a vegetarian diet and tried my damndest to get all the nutrients without meat. But after some time I always felt full but malnourished. It is hard to describe. I broke eventually and spent about 3 weeks eating some red meat every day until I felt like my normal self again. I still try to minimize my meat consumption, but I've definitely learned to notice a threshold where I need to supplement my doet with meat on occasion.

I fear that often the vegan community insists that these lifestyle changes are universally easy. It probably doesn't help that many of the vegan activists make a part of their living by being vegan activists, which gives them flexibility to micromanage their diet. But for the gentleman at the lumber yard, it isn't so easy.

I'm excited to see cultured meat make some headway and hope the ventures in this space are successful. I've been watching for some time.

How is an example of doing a tail activity like competitive powerlifting and the anecdote of underperforming in the activity on a vegan diet relevant?

I am pretty sure that gentlemen at the lumber yard do not have 300kg deadlift events and are not competing.

It is well known that diet has very little to do with progress for an amateur athlete. Consistency is the biggest factor in long term success. If you want to eek out the most out of your body, then you might want to optimize, but then you're already deviating to obsessive behavior.

Yeah, if you want to increase your squat by 20% short-term, you're going to have to eat more food and be obsessive about it, but if you're fine with consistent training over a span of 10-20 years, there's no reason to stress too much about diet.

When I hear people talking about diet and "optimal performance", I always wonder what the hell are they doing that they need to optimally perform. Like, what exactly is optimal performance of a sedentary programmer that maintains elasticsearch clusters? What, he feels tired sooner if he's on a vegan diet instead of something else?

I’d be curious about other mental health / unprocessed traumas that the ex vegans hadn’t addressed.