A year and a half ago I wrote about protein and mentioned that one day I would have time to dig into the debate of protein – how much and plants vs animals. Well ladies and gentlemen – lets get ready to rumble (read in your Michael Buffer voice if you can for effect 😀 )
I eat soy almost every day. Tofu, edamame, tempeh, soy milk. I am 44 with about 10.4% body fat. Over the stretch where I was eating more tofu and beans than at any point in my life, my total testosterone went from 348 to 744. My hs-CRP, the inflammation marker that once had me convinced I was headed for a heart attack, went from 4.0 to 0.2. I believe that was heavily influenced by supplementing with some algae based omega-3 supplements and upping my flax and walnut intake. Many get theirs from fish – I choose plant sources.
I think I’m in pretty good shape and wanted to share with you - I do not have man boobs. Because if we’re being honest – that is the boogieman of the protein discussion as it relates with soy.
To be totally clear: I changed several things at once. More protein and more calories. Also enzymes so my gut finally absorbed what I was eating, heavier lifting, better sleep, less packaged food. Soy and legumes and some quinoa was how I got the protein. There are many factors to naturally increasing testosterone.
The mystical number of protein per pound
Seventy percent of Americans said last year they were trying to eat more protein. In the same survey, 53% said they had no idea how many grams they should eat. Among the few who said they did know, most named a number lower than what the average American man already eats without trying.
The 0.8 grams per kilogram printed on food labels your whole life and my whole life comes from an analysis of 235 people. What it measured was nitrogen going in and nitrogen coming out. Not muscle. Not strength. Not anything you would recognize as health.
In January the US government moved the cheese. The 2025-2030 Dietary Guidelines set the adult goal at 1.2 to 1.6 grams per kilogram, roughly double the old number. I’m going to say follow the money to Big Protein – is that a thing?
Then there is the gym rule. A gram per pound is 2.2 g/kg for every person alive, since a pound is 0.4536 kg. It traces back to one meta-analysis of 49 trials that found gains stopped at 1.62 g/kg. In the paper, the breakpoint was not statistically significant, and the range around it ran from 1.03 all the way to 2.20. The authors noted that since the range reached 2.20, maybe recommend 2.2. The rule our trainer treats as biology is the top edge of a confidence interval. In other words, we are guessing.
For me, the range is 60 grams at the old label number, 120 at the top of the new federal range and more if I go for one gram per pound.
I tried to hit close to 160 for a while - on three meals per day – 5 hours a part and eating healthy and whole food plant based – that is a job my friends.
I do see value in protein, but stressing about how much makes eating pretty miserable if you want to abide by my no snacking and 3 meals per day plan.
Separate research groups using different methods keep arriving in the same neighborhood: 1.5, 1.6, 1.62. And the average American man already eats 97 grams a day, a figure that has not budged in a decade despite the entire protein boom.
Does the source matter?
A little bit and a whole lot less than the shouting match would make us think.
On the scale researchers use to score protein quality, tofu comes in at 0.97. Whey protein isolate is 1.09. Collagen, sold in tubs as a protein supplement, scores 0.0, because it contains no tryptophan at all.
In the study most often used to prove plant protein is inferior, whey did beat soy after a workout. The part nobody quotes: in that same experiment, soy beat casein, a dairy protein, by 69%. I’m not here to demonize your favorite protein - if its a clean source, go for it.
Let me stop here and say there is an argument amidst this protein debate for muscle growth and arguments for better sleep and longevity and overall health – choose wisely – and carefully.
Also, someone ran a trial: Vegans and meat eaters, both lifting for 12 weeks, protein matched at 1.6 g/kg. Identical muscle gained. Both groups, 1.2 kg.
A 2025 review of 30 trials did find animal protein ahead in many categories overall, with the gap around rice, oat, chia and potato. Soy against milk was a tie.
Soy is also not incomplete. It carries all nine essential amino acids. It runs slightly short on one pair, which eating it alongside grains takes care of.
About the breasts on men
Forty-one clinical studies have measured what soy does to male hormones. Total testosterone in 1,753 men. Free testosterone in 752. Estradiol in 1,000. No effect on any of it, at any dose, over any length of time.
So where did this issue come from? Two men.
One was a 60-year-old drinking three quarts of soy milk a day. Twelve cups, every day. His doctors only found the soy after every scan came back clean. He stopped and it resolved. The other was a 19-year-old eating almost nothing but soy. He stopped and it resolved.
Meanwhile, when doctors fully worked up 237 men with confirmed gynecomastia, the leading identifiable cause was anabolic steroids. Soy is not on their list anywhere. What shows up again and again is body fat, since fat tissue converts testosterone into estrogen. In one survey, more than 80% of men with a BMI over 25 had palpable breast tissue.
Two facts worth setting next to each other. Cow's milk contains real human estradiol, the actual molecule, about 1 picogram per milliliter in whole milk. Soy contains none of it. And the most potent plant estrogen anyone has identified is not in tofu. It is in beer hops, and it favors the very receptor that soy compounds steer away from.
The food carrying the actual hormone is one we don’t hear any warning about – beer.
My takeaway - Eat the soy - bean. Not the soy - powder pressed into something shaped like a candy bar.
How to Flourish
Find your number, then stop worrying about it. Pounds divided by 2.2, then times 1.6. For me that math lands near 120, and I aim for around 100 and stop stressing about it. Past about 1.6 grams per kilogram, nothing has been shown to add muscle.
Move some of it to breakfast. Americans eat only 16% of their protein in the morning and nearly three quarters at lunch and dinner. The hole is early in the day, not at the end of it. Eat breakfast like a king – dinner like a pauper.
Buy soy that still looks like a bean. Tofu, tempeh, edamame, miso, natto. If it arrives as a powder inside something else, you are not getting the best version.
Get lean before you blame the tofu. Body fat is the mechanism nobody wants to hear about, and it is the one with the evidence behind it.
-Jared
P.S. - My wife Baddie Crocker has a beautiful newsletter where she shares her perspectives on tending the land, recipes, women’s health and more.
I’d love to hear from you. 👋
P.S. - This newsletter does not provide medical advice. The content, such as graphics, images, text, and all other materials, are provided for reference and educational purposes only. The content is not meant to be complete or exhaustive or to be applicable to any specific individual’s medical condition.
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