I suggest researching dentistry and omnivores and humans.
Some basic evidence to prove we are omnivores relates to our teeth. We have incisors and canines (which are carnivore teeth); and we have pre-molars and molars (which are herbivore teeth.
We are not "carnivorous omnivores" like cats. Cats literally cannot survive without meat. We can, but it takes a lot. Also, consider looking at "protein absorption and humans".
When humans absorb amino acids (the building blocks for protein), we actually have a "all-or-none" system. This is common with omnivores and carnivores. This means we need the entire compliment of amino acids to create a protein that we can use. Thus, in order to be an herbivore, we would need to eat bread and beans together, for example.
I hope that helps you! You can always contact me if you need more assistance.