> Aren't low testosteron levels a bigger issue?

Nope. Vegans have higher T levels. Also higher than vegetarians. Here an article with plenty links to studies:

https://nutritionfacts.org/2013/02/12/less-cancer-in-vegan-m...

Linking to nutritionfacts.org is like linking to Exxon with an article on why green energy is bad.

It's not like the "tofu shuts down all your male hormones!" meme is anything more than bro science.

What does nutritionfacts.org sell? Broccolli?

Does nutritionfacts.org pay for studies? Nope. (Exxon does)

Sorry, bad comparison. But I understand what you mean: Greger eats a plant based diet himself so he must be biased and the probably goes about cherry picking studies to match his beliefs. After a lot of research I've come to the conclusion he's honest and works in the interest of people's health.

> What does nutritionfacts.org sell?

A religion.

So the article that you linked focuses on cancer, and even the claim about testosterone links to another article on the site that also focuses on cancer and not on testosterone.

Turning to the article's sources, you find [1] source for the testosterone claim. And the summary at the beginning of that study states the following:

"Vegans had higher testosterone levels than vegetarians and meat-eaters, but this was offset by higher sex hormone binding globulin, and there were no differences between diet groups in free testosterone, androstanediol glucuronide or luteinizing hormone."

So higher overall testosterone, the same amount of free testosterone. I think this is a perfect example of selectively reporting on scientific studies. The author of that article may not technically be wrong, but it encourages spreading bad advice when you repeat that claim over and over again without the caveats mentioned in the actual studies.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2374537/pdf/83-...

It's worth noting that it's even in the title of the study: "Hormones and diet: low insulin-like growth factor-I but normal bioavailable androgens in vegan men". There's no excuse for misrepresenting that.

It's not, some people just make an assumption that vegan = just vegetables, and that you're not getting any protein.

Where are you basing the assumption that low testosterone happens from a vegan diet?

There have been studies that show high concentrations of estrogen-like compounds in soy-based products. People trying to maximize their testosterone levels while ingesting high amounts of protein are generally advised to stay away from soy

Edit: here's an article from a bodybuilding website that tries to summarize the conclusions of various journal articles on the topic:

https://www.bodybuilding.com/fun/ivan3.htm

What about the actual bovine estrogen in any milk product?

Edit: Here's a link to an article discussing how much soy is too much: https://nutritionfacts.org/2013/02/19/how-much-soy-is-too-mu...

For what I know that effect is negligible. Here's a review of some studies on the topic:

https://nutritionfacts.org/video/who-shouldnt-eat-soy/

See my other comment on T-level being higher in vegans (Even higher then in vegetarians). There's a huge vegan-fitness movement going on, and it rapidly moving into professional sport in general. They simply self-report to perform better, thus stick to the diet.

This article basically says soy protein is great.

I don't agree that soy is bad for you, I was just trying to give the parent comment a reason why others might find issue with it.