Parents are under intense pressure to introduce their children to nutritious foods as early as possible. And the advice on how to do this has changed dramatically over the years, from breast milk to formula to commercial baby food, back to the breast, and then homemade organic broccoli mash. (See What’s Best for Baby’s Tummy? The History of Baby Food.)

When a baby reaches four to six months old in the U.S., she is commonly treated to spoonfuls of bland rice cereal or oatmeal, followed by a slow and careful parade of fruits and vegetables like avocado, sweet potato, banana, carrots, and peaches. Then there’s the question of when to introduce peanuts or shellfish, which could cause an allergic reaction in sensitive babies, and there’s the