1. Dina M. DiMaggio, MD*,† 2. Amanda Cox, MD‡ 3. Anthony F. Porto, MD, MPH§ 1. *Department of Pediatrics, NYU Langone Medical Center, New York, NY 2. †Pediatric Associates of NYC, New York, NY 3. ‡Division of Pediatric Allergy, Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY 4. §Section of Pediatric Gastroenterology, Department of Pediatrics, Yale University, New Haven, CT * Abbreviations: AAP: : American Academy of Pediatrics ARA: : arachidonic acid CDC: : Centers for Disease Control and Prevention DHA: : docosahexaenoic acid FDA: : Food and Drug Administration FPIES: : food protein–induced enterocolitis syndrome GER: : gastroesophageal reflux GERD: : GER disease IgE: : immunoglobulin E MCT: : medium-chain triglyceride WHO: : World Health Organization Guidelines for introduction of complementary foods in infants have evolved. New data have led to the development of updated guidelines on the introduction of high-allergy foods, especially with the introduction of peanuts. Pediatricians need to keep up to date with these changes to educate parents on current guidelines. After completing this article, readers should be able to: 1. Educate parents on the introduction of complementary foods, specifically with regard to iron- and zinc-fortified first foods and highly allergenic foods, including peanuts, on the basis of current guidelines. 2. Use the World Health Organization and US Centers for Disease Control and Prevention growth charts correctly. 3. Recognize and treat common medical conditions related to infant nutrition. 4. Describe the differences between common infant formulas. Infancy is a period of rapid growth and development. Parents are often confused about optimal infant nutrition practices. In addition, as new research has emerged, pediatricians have needed to modify the education provided to parents. This article covers common topics about infant nutrition, including normal infant growth, use of breast milk, discussion of formula options, and introduction of complementary foods. Our recommendations are based on current guidelines and research. During infancy, children are expected to double their birth weight by 5 to 6 months of age. Children gain weight more rapidly during the first 3 months after birth, and this rate decreases over the first year (Table 1). Height will also increase by 10 inches (25.4 cm), and head circumference will increase by 5 inches (12.7 cm) in the first year. View this table: Table 1. Normal Infant Weight Gain A good resource for identifying patterns of excessive weight loss in the first few days …