Dr. Shawn Baker challenges vegan jihadis, eats only meat for 15 months. Think he's unhealthy? Here's what happened...

[palou]

John2290 said:

palou said:

For the example of spiders, there's a rather obvious relation. Spider's don't have lungs, and aren't able to distribute  oxygen throughout their bodies correctly, if there isn't sufficient oxygen. They die, if they're too big. So, smaller spiders survive. Simple as that.

Humans don't die, don't become infertile, etc... when they have a vegan diet, and a smaller brain certainly doesn't compensate for that in any way. The evolutionary drive just isn't there. 

Tell that to people with alcohol fetal syndrome, people born from drug addled mothers. Just as those people have to deal with the consequences of not getting the proper diet at the right time. Desendants of Vegans will suffer in the same way, most likely the first signs through the generational leaps being mental more than physical. Sure this could be fixed if it was just a few generations but like I mentioned in the case of the appendix, no amount of grass in your diet is bringing the thing back to life. You are speaking in a complete chicken or egg situation but life and evolution is more nuanced that and the small changes have massive effects over long periods of time. Even in the short term on scales we can imagine, you can see a Vegans mental state change before your eyes in a negative way in the first few months and it's not a pretty sight. 

Again, why would the adaption process to a vegan diet cause a decrease in brain size? 

Even if a parent has a bad mental state, you don't *inherit* that. Lamarckism is a theory that's been abandoned for a long time, already. For evolution, you need evolutionary drive.

The hormones that cause mental state just don't require significant building materials (and you can find those building materials in just about anything, just in different proportions...). IF there are any immediately noticeable effects, these are due to reactions, from the body, to something it's not used to - rather than an inability to maintain production. The natural evolutionary step is losing those reactions, not losing brain capacity.