Grains

Naturally gluten-free grains and pseudocereals include rice, corn, millet, sorghum, teff, buckwheat, quinoa, amaranth, and uncontaminated oats. Wheat, barley, rye, spelt, kamut, and triticale contain gluten and are not suitable for celiac disease or gluten sensitivity. Oats are biologically gluten-free but are often cross-contaminated, so people with celiac disease should choose products specifically labeled gluten-free.

Whole grains retain all three parts of the kernel: bran, germ, and endosperm, preserving fiber, B vitamins, vitamin E, magnesium, and phytochemicals. Refined grains have the bran and germ removed, leaving mostly starchy endosperm, which lowers fiber and micronutrient content. In the United States, refined wheat flour is typically enriched with thiamin, riboflavin, niacin, folic acid, and iron, but fiber and magnesium are not added back.

Most grains provide moderate protein, roughly 7–14 grams per 100 grams dry. Quinoa, amaranth, oats, and kamut are on the higher end, with quinoa also offering a more complete amino acid profile including lysine. Standard cereal grains are limited in lysine, so combining them with legumes such as beans or lentils improves overall protein quality.

Lower-GI options include pearled barley (GI around 25–35), bulgur, steel-cut and rolled oats, whole rye, quinoa, and parboiled or basmati rice. Higher-GI grains include instant oats, jasmine and short-grain white rice, rice cakes, and most products made from refined wheat flour. Cooking method, particle size, and pairing with fat, protein, or fiber all influence the actual glycemic response.