We have both canines and flat molars which makes us naturally suited for an omnivorous diet.

We don't need giant teeth for two reasons:

• First, because our ancestors discovered how to make stone tools at least 2.6 million years ago...and they used them to deflesh carcasses. In fact, we have evidence that they were defleshing bones with naturally occurring rocks 3.4 million years ago (Dikika).

• Second, because our ancestors discovered how to cook food...and while there is no evidence that it happened as long ago as Richard Wrangham thinks (remember, he's a vegetarian trying to justify vegetarianism), we have solid evidence that our ancestors could create fire at will for several hundred thousand years, and that we used it when available for perhaps a million years.

• Third, huge canine teeth are as often a threat/combat display as a meat-eating adaptation. Here's a Chinese Water Deer (vegetarian):

And here's our friend the chacma baboon, which has longer fangs than a lion despite its mostly-vegetarian diet:

JS

Tell them we do have teeth for eating meat. Offer to bite them if necessary.

Our teeth are a hybrid design.

http://youtu.be/VejLXTsJrJc

This topic relates to the "what are we meant to eat" discussion.

We invented this thing called cooking with our big, nerdy brains. Anyone that argues that cooking is unnatural has no knowledge of human evolution. We've used our intelligence to overcome physical shortcomings.

Actually if you look at our entire body and each individual part, humans only have a few traits in common with pure carnivores. One simply can not look at each individual part,but must look at sum of those parts and how they work (There function). Most vegetarians will say that our teeth are more like herbivores, which is true. This is mostly because hominins evolved alongside tool use. The trait of having larger-sharper canines did not get selected for because we could use tools to chop down, and after a hundred thousand years cook, our meat. We retained mostly flat molars because hominids still relied on nuts and vegetables. A vegetarians forget that if it wasn't for the first hominids scavenging for meat then our brains would not have the opportunity to become so complex though out evolutionary history, therefore we wouldn't even be able to use language to discuss the issue.

Get a copy of The Vegetarian Myth.

Just smile and offer to take a bite of them with your teeth.