This is from an article last week on Dr. Mehmet Oz’s site written by Dr. Mark Hyman. It's called "The Anti-Allergy Diet" and this is the lead: "Are hidden food allergies making you gain weight? Mark Hyman, MD, has a 3-week anti-allergy diet to help get your system back on track so you can start shedding pounds."
Food allergies are very serious and can be life threatening; a food allergy does not cause weight gain. The only “anti-allergy” diet for those of use with an IgE mediated food allergy is strict avoidance of the allergen. Go to reliable medical source for information about the difference between food allergy and food intolerance. If you suspect you have a food allergy, see a board certified allergist.
Here's a helpful video about food allergy (specifically peanut allergies) from Dr Robert Wood at Johns Hopkins hospital (through Kids with Food Allergies).
Here's another helpful series of slideshows and videos about food allergies from my colleague Dr. Mike Pistiner.
And you can find all the top websites for reliable food allergy information on my website Allergic Girl.