[aashay]

I'm not sure how involved you guys get with the post-delivery processes (i.e. what the companies do with the food after it's delivered), but here's an idea you can communicate to try and solve that: One of the things I asked our lunch caterers to do was to put the vegetarian food at the very end of the lunchline. People tend to pile their plates with the food they see first (I believe Google modified its lunchlines to include healthier food at the start of the line due to this phenomenon [0], which is what gave me the idea) so if the vegetarian food is at the end, the omnivores will have less room on their plate for what they sometimes perceive as side dishes.

It worked. Our vegetarians always have food to eat now (there's even leftovers).

Of course if you don't have an ordered line, just have a vegetarian volunteer run over and horde/separate all the vegetarian food before the others get to it. This is what we do for dinner.

[0] Source: http://www.bonappetit.com/blogsandforums/blogs/badaily/2013/...

Edit: Added source for the Google article