Gluten-free food is normally seen as a diet for celiac disease, but people with a gluten allergy (an unrelated disease) should also avoid wheat and related grains.

Several grains and starch sources are considered acceptable for a gluten-free diet. The most frequently used are corn,potatoes, rice, and tapioca (derived from cassava). Other grains and starch sources generally considered suitable for gluten-free diets include amaranth, arrowroot, millet, montina, lupin, quinoa, sorghum (jowar), taro, teff, chia seed, almond meal flour, coconut flour, pea flour, cornstarch and yam. Sometimes various types of bean, soybean, and nutflours are used in gluten-free products to add protein and dietary fiber.

Almond flour has a low glycemic index. Despite its name, buckwheat is not related to wheat. Pure buckwheat is considered acceptable for a gluten-free diet, however, many commercial buckwheat products are mixtures[citation needed]of wheat and buckwheat flours, and thus, not gluten-free. Gram flour, derived from chickpeas, is also gluten-free (this is not the same as Graham flour made from wheat).

Gluten may be used in foods in some unexpected ways, for example it may be added as a stabilizing agent or thickener in products such as ice-cream and ketchup.

A gluten-free diet rules out all ordinary breads, pastas, and many convenience foods; it also excludes gravies, custards, soups, and sauces thickened with wheat, rye, barley, or other gluten-containing flour.