Higher Childhood IQ = Higher Likelihood of Being Vegetarian
This study came out that shows that smarter children tend to end up being vegetarian later in life. Of course, that doesn't mean they're healthier. Many smart people tend to overanalyze things and like to hold the "moral high ground." There is likely some carryover of that into vegetarianism as the smart folks strive to be above us heathens that would dare eat animal flesh. However, those that listen to their bodies know that animal products are necessary for optimal healthy.
One interesting finding:
The study found that vegans had an average childhood IQ score that was nearly 10 points lower than other vegetarians (95.1 for vegans versus 104.8 for other vegetarians; P=0.04). However, this result could be unreliable because of the small sample size: only nine study participants were vegan, the authors noted.
So called ovo-lacto vegetarianism can be done in a healthy way if one pays attention to ensure enough protein and fat are taken in. On the other hand, veganism is a wholly unhealthy endeavor, only being categorized as healthy because it is healthier than the SAD (Standard American Diet). Humans evolved to eat animals and our genetics simply will not allow us to thrive without the high-density energy sources that are animal flesh, along with the vitamins that are only available in animal products.