Eating a balanced diet seldom diverts the body to ketosis mode. And, as important as it is to come up with a list of foods you can eat, to be successful on a vegetarian ketogenic diet, you may also want a list of foods you can't eat (i.e., those that will throw you out of ketosis state). As with any ketogenic diet, there may be unpleasant (and unhealthy) side effects like constipation, bad breath and keto flu.