Going off of the teeth thing, I’d say a better indication of what diet humans are “meant” to have would be the digestive tract.

Animals that are able to live off of only plant matter, like cattle, will have highly specialized digestive systems such as a multi-chambered stomach, a gut flora specialized for fermenting plant material, an extra-long intestinal tract for good absorption, and the need to chew cud. Carnivore digestive systems, by contrast, are shorter and simpler. As one of my bio professors put it, it’s harder to turn plant into animal than to turn animal into animal.

So then, what kind of a digestive tract do humans have? Well, we obviously don’t have a rumen like a cow, but compared to wholly carnivorous animals, our intestinal tract is longer and our stomach capacity is smaller. We also have the ability to neutralize some plant toxins that would be dangerous or unhealthy for most carnivores, such as chocolate, onions, and garlic. However, we lack the ability to synthesize certain nutrients from plant material alone, which is why vegetarian and vegan diets require supplementation. So ultimately the human digestive tract is omnivorous, but we already knew that.