[pheroden]

Some soy is fine, but if we're talking as completely replacing your meat, it could be too much estrogen like compounds. Hence breasts in men and an increased risk of breast cancer in women. I haven't seen enough studies to definitively rule these out.

Besides, variety is always good. It's never wise to put all your eggs in a single basket.

[noondip]

> Some soy is fine, but if we're talking as completely replacing your meat, it could be too much estrogen like compounds.

Are you aware there's estrogen found in virtually all animal products, in concentrations and potency many times greater than any phytoestrogens could possibly deliver?

> Hence breasts in men and an increased risk of breast cancer in women.

Your source for this claim? I've only found evidence to the contrary, e.g.,

"Thus, the evidence to date, based largely on case–control studies, suggest that soy food intake in the amount consumed in Asian populations may have protective effects against breast cancer. Overall data based on Asian women, mainly derived from case–control studies, show a dose-dependent, statistically significant association between soy food intake and breast cancer risk reduction. There was an approximately 16% risk reduction per 10 mg of isoflavones intake per day."

https://www.ncbi.nlm.nih.gov/pubmed/18182974

"This nested case-control study found an inverse association between plasma genistein and the risk of breast cancer in Japan."

https://www.ncbi.nlm.nih.gov/pubmed/18316793

"Soy isoflavones consumed at levels comparable to those in Asian populations may reduce the risk of cancer recurrence in women receiving tamoxifen therapy and moreover, appears not to interfere with tamoxifen efficacy."

https://www.ncbi.nlm.nih.gov/pubmed/19221874

"In summary, this follow-up study among a population-based sample of breast cancer patients suggests that there may be a beneficial effect of high intake of flavones and isoflavones on all-cause mortality."

https://www.ncbi.nlm.nih.gov/pubmed/18006917

"Our study is the third epidemiologic study to report no adverse effects of soy foods on breast cancer prognosis."

https://www.ncbi.nlm.nih.gov/pubmed/21357380

[pheroden]

Hey, that's great, I hadn't done a deep look for a while. Regardless, my point was more with using it as your only source of protein, which none of these address.

[noondip]

Considering every whole plant food is a complete protein source, a diet consisting of only tofu is impractical and unpalatable, which is why you'll unlikely find such a study.

[aparent]

A small addition to noondip's reply:

"Clinical studies show no effects of soy protein or isoflavones on reproductive hormones in men: results of a meta-analysis." https://www.ncbi.nlm.nih.gov/pubmed/19524224

Also you say that you have not seen enough studies to rule these out; what studies have you seen to make you believe they might be an issue?

[tomp]

There's just one thing I don't get... Too much carbohydrates are supposed to be bad. Too much soy is supposed to be bad. But the Japanese live the longest, so obviously they can't be that bad. So one of these assumptions must be false:

- Japanese eat a lot of rice and/or soy (or products made from them) - Japanese have different genetics that allows them to avoid the negative effects of carbs/soy.

We could probably throw fish (mercury) in the mix as well.

[dmm]

How much of the japanese diet is actually made up of soy? The numbers I've seen are <5%.

[lifeformed]

It seems like it'd be much more than the 100-200g/wk that they suggest. In China or Taiwan, every day you could drink a big bowl of soy milk for breakfast, and for lunch/dinner eat some mapo tofu, stir fried bean curd sticks, etc.

[ekianjo]

I confirm it should be more than that. Miso soup is a daily dish in Japan for about one or 2 meals, and it usually contains 20g of Tofu at least. Then there's soy beans, used in many delicacies, soy sauce used for sushi, a number of dressing using soy as a base...

100-200g/week actually seem a rather low estimate in Japan.

[noondip]

> Too much carbohydrates are supposed to be bad.

Carbohydrates are your body and brain's preferred energy source. What makes you think consuming too many is, "bad"? If derived from whole plant sources, carbs are fantastic and shouldn't be restricted.

[jp555]

by the time it hits the bloodstream the carbs in an apple and those in a bowl of lucky charms are identical. it's all broken down into identical fructose and glucose molecules.

[noondip]

The processes by which the two "hit the bloodstream" are quite different. For example, an apple has fiber and phytonutrients which slow the absorption of glucose. Whole fruits are so unlike processed breakfast cereals, I think it's a stretch to say their metabolization is identical.

[jp555]

yep, but 100i/h for 1h vs 10i/h for 10h is the same amount of energy in the end. I didn't mean to say the metabolization is the same at all, and absolutely fibre makes a huge difference, but that's a different macro nutrient from the sugar (fructose/glucose) content.

[SolaceQuantum]

Actually the Japanese and also many Chinese are running into problems with health because of high salt and such. Soy not as much, and I don't really believe the breast cancer stuff or east asian countries would be the no.1 place for those kinds of cancers.

[jp555]

You think it's salt and not increasing obesity rates?