Or it could be that Happiness = Vegetables. Either way, researchers have established a correlation:
People who eat more vegetables and fruits are significantly happier than those who eschew such foods.
Dartmouth University’s Daniel Blanchflower looked at the eating habits of 80,000 British citizens. He, alongside two British researchers, saw that mental well being — satisfaction with one’s life on a scale of one to 10 — rose alongside each serving of produce consumed daily…
[snip]…There is one big, outstanding question that he acknowledges: What’s the causal relationship? It could be that eating vegetables make people happy — or that happier people tend to chow down on more salads.
“It might be that we just have all these vegetarians that are richer or happier,” Blanchflower says. “There are definitely issues of causality. At the same time, I think what we’ve done here is establish correlation. I don’t think we expected to see the relationship we did. The reason you’re calling me is because this was unexpected.”
Nevermind they haven’t figured out which way the causation runs. The correlation alone is just one more reason to eat like a vegetarian and think like a vegetarian.
Now all they need to show is that vegetarians have more sex and we’ll be getting somewhere.