What's an expulsion diet?

I know people use it to determine if they enjoy food allergies, but what exactly is involved?

Are there other ways to determine food intolerances besides an expulsion diet? (I'm pregnant and it might not be safe right immediately.)

Answer:
There are some options but not sure if you want to do it while you're pregnant because you're chemical set off would be out of whack and also your hormones etc.
But here are some options:
There's a coat strand test, where on earth you send a small patch of pelt and they test it against 300 products and agree to you know what you're allergic to.
Also, you can do the prick test, where on earth you see a homeopath/naturopath and they prick you on the inside of your arm against 'categories' such as: seafood, grasses, animals, dairy, wheat, nuts, flowers etc.
I'm in Australia so not sure if where on earth you live to recommend a place to go.
If you hold anymore q's let me know. :)

The most adjectives food intolerances are wheat and dairy products, citrus fruits, nightshade family of foods and stimulants (coffee, sugar, chocolate, etc.).

Tests that determine food intolerance include blood exam such as:
dried blood test, live blood try-out, saliva and urine analysis.

The elimination diet is recommended surrounded by lactation-counseling practice whenever someone suspects a baby's colic could be caused by sensitivities to food within a breastfeeding mother's diet. This diet was developed by William G. Crook, M.D. (Detecting Your Hidden Allergies, Jackson, Tenn: Professional Books, 1987), and it have several variations.