Adverse effects from a cat eating dog food?

My cat will sometimes get a snack from my dogs food bowl. I don't allow it but sometimes I'll catch her eating dog food. I'm not too worried about it because she doesn't get much. She absolutely loves it though, maybe because it's grain free and hers isn't? I'm just curious as to what would happen if she ate a lot at once (mainly due to the vitamins and supplement differences). Thank's in advance! 

I think the worst that would happen is that she might throw up or get a bit of intestinal distress.  The real problem comes when cats eat dog food long term instead of their own food. And you're right - the reason is because of the different nutritional requirements.   One binge shouldn't cause any lasting damage.

Yeah, a few dog kibbles now and then are fine. Or even one whole meal of dog food wouldn't hurt (if she managed to steal that much! Unless she's the type who gets sick from different foods). It's long-term feeding of dog food that's the problem---that will cause vitamin deficiencies.

She's just always loved dog food for some reason. None of my other cats do. I'm thinking she might like the grain free food more because it meatier. 

cats often have a hard time digesting grains. Is there a possibility of switching her to a grain-free cat food? She might find it more satisfying and possibly even make her less interested in the dog food.