I don't know if there is much of a difference when it comes to intelligence and smartness when it comes to diet, as long as nutritional requirements are met, but my personal experience is that veg meals are far lighter on the stomach.I'm not much of a non-veg eater in any case, being born into a vegetarian family. Not that I avoid it, but if the choice is between veg nad non-veg..... the non-veg had better be cooked in a really mouth-watering way :PIf any thing, a difference I notice seems to be that the vegetarians are sharper, while the non-vegetarians seem to be bolder. This may not necessarily be due to the diet though. A lighter stomach, my perceptions of people, or cultural influences on both attitude and diet could also be the cause behind it.Can't say. I guess our bodies work best on whatever food we've been brought up on since childhood, as we adapt to using nutrients most effectively from that kind of food.As far as I'm concerned, I am unlikely to consciously restrict myslef to any kind of food, but that doesn't mean much either, since my last non-veg meal was eggs and it happened 2 months ago