Possible Clues:

• High-protein grain
• South American goosefoot with seed used like rice
• Protein-rich grain
• One of five children initially orders all vegan food
• South American grain
• 'Supergrain' used in some gluten-free recipes
• "Supergrain" used in some gluten-free recipes
• Grain-like crop from South America
• Vegan food, one of five consumed daily, in seconds
• Couscous alternative