Food allergies, intolerances and sensitivities are so common it's getting impossible to cook a meal for friends without taking a medical history first. Ask anyone and I bet they'll tell you that they react to peanuts, gluten, corn, soy, egg, yeast, shellfish or strawberries.
Elimination diets are tough! But the fact is that nothing else really has the same impact. Eliminating gluten, dairy and sugar will make the most immediate difference whether your symptoms are weight gain, headaches, joint pain or depression.