The soy-free diet is eaten by people who are allergic to soy, one of the most common food allergies in infants, young children, and adults. These people are required to eliminate all foods that contain soy or soy products in order to avoid unpleasant allergic reactions. Most people who are allergic to soy are allergic to the protein in soy. Soy oil and soy lecithin pose little risk of causing an allergic reaction in most, although not all, soy-allergic people because processing removes almost all the protein.

• Read labels carefully to determine if a soy product is included and avoid any food you’re not sure about until you are able to verify that it is soy-free.

• Learn the technical and scientific terms for soy so you can recognize them on food labels: tofu, edamame, miso, tempeh, momodiglyceride, textured vegetable protein, soy protein isolate, and so forth.

• Ask at restaurants and at others’ homes to be sure the food you are being served is soy-free.

Best bets: Look for nonsoy protein sources such as veggie burgers (be careful to read the label—not all of these will be soy-free), wheat gluten, seitan, and meat products, and cow’s milk, rice milk, and almond milk.