1. The importance of breakfast for 3-year-old babies Three years old is a critical period for the growth and development of babies, and every meal is very important. Breakfast is the most important meal of the day, especially for a 3-year-old baby. Good breakfast habits can help your baby stay healthy, improve immunity, promote intellectual development and improve learning ability. 2. What foods should be included in breakfast for a 3-year-old baby? 1. Cereals: You can choose whole-wheat bread, oatmeal and other cereal foods, which are rich in carbohydrates.