Is it bad if my cat eats my dog's food?

My dog's food bowl is sitting out with what he has not finished from dinner yet.

It's a combination of his usual food, mixed with a new food, and my cat keeps going over to his bowl and trying to eat it. She doesn't usually do this, so I assume it's because of the new food. She has a full bowl of her own food and I even took her to it to show her.

I don't want to pick his food bowl up yet, because sometimes he goes back and eats a little here and there. If there is still food left when I go to bed, I pick it up then.

By the way, I should add, I'm stopping her when I catch her. I just want to make sure if she does eat some before I notice, is it okay?