Try hosting a dinner party and you'll likely be confronted by one of the most compelling food fads of the moment—the elimination diet. While the practice of singling out a dietary super-villain was formerly reserved for food-allergy sufferers, health buffs are realizing that smart exclusions can reap big rewards. 

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While only 3 percent of people have a true food allergy (a shrimp cocktail or strawberries send them into anaphylactic shock), food sensitivities are much more widespread. "You may have stomach pain or bloating," says Dr. William D. Chey, a gastroenterologist and professor of medicine at the University of Michigan. "But it can also show up as fatigue, joint pain, or mental fogginess." 

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Eating foods that you may be sensitive to also creates inflammation, which may block key messages from reaching your brain—including the ones that tell you to stop eating or tell your body to burn fat or regulate blood sugar. So should you scrap moderation for hard-and-fast elimination? Maybe so.

"Moderation is how you get fat—one cookie at a time—and it takes twice as much effort to undo that damage," says JJ Virgin, a nutritionist and the author of The Virgin Diet. What works, he says, are the easy-to-follow rules of food exclusion—you don't have to think twice about what to eat and, more important, what to turn down. 

Read on for the six ingredients to eliminate and what to swap in their place.