Depending on the allergy, suitable substitutes include quinoa (gluten-free, high protein), millet (mild flavor, gluten-free), cauliflower rice (low-carb, vegetable-based), or buckwheat groats (nutty, gluten-free despite the name). Choose based on texture and nutritional needs.
Adjust cooking times and liquid ratios because these grains behave differently. For baking or puddings, consider oats or tapioca depending on the recipe.