Here's the story as simply as I can give it to you.

There's a diet, the Ketogenic diet, that has been found to stop epilepsy in many cases. It's still a bit controversial, but a lot of folks swear by it.

Some researchers have found that altered state experiences can be explained explained as transient episodes of a certain type of epilepsy (Called complex partial seizures).

In some separate research, it was found that the amount of altered states people have is a kind of spectrum. Only a few people never have them, and only a few people have them all the time. Most people fall somewhere in the middle. You don't have to be an epileptic to have these experiences.

If altered states and epilepsy share a mechanism in common, then if you find that you're having a hard time staying 'grounded', then the ketogenic diet might just be the thing to help you out.

The Ketogenic diet is a carefully calculated, high fat, low protein, virtually carbohydrate-free diet that is used for the treatment of Epilepsy. Interestingly, this diet is quite the opposite from the diet that most mystic traditions (who have dietary restrictions) suggest.

P.M.H. Atwater, who works with Near-Death Experiencers, and has had three such experiences herself, commented that the most grounding food she could find was Mcdonald's French fries, and many of the people she worked with agreed.

French fries, being greasy, are specifically allowed in the Ketogenic diet.

My conclusion is that its possible that the ketogenic diet could be a way to stay grounded for those who need it.

I don't know this with the force of clinical studies to back it up. (The word 'grounded' is a bit troublesome for epileptologists, too.)

Perhaps there will be a study in the future. But its a simple, dietary solution, and unless it conflicts with allergies for a person, I don't see how it can do any harm, and the case in favor of it seems fairly solid.