Nutrition is a known, powerful determinant of perinatal health and one that is increasingly recognized to have further reaching effects than previously understood. It is well known that healthy nutrition during the peripartum period can prevent birth defects in the neonate. New research suggests that peripartum nutrition may also modulate the risk of chronic disease in later life. Proper nutrition and weight gain during pregnancy also have maternal benefits including lowered risks of pregnancy related disorders. Good peripartum nutrition is a potential tool to impact the rising prevalence of obesity and related health disorders. This article will review nutrition guidance in pregnancy including macro and micronutrient recommendations, newer recommendations for appropriate weight gain based upon body mass index categories, and avoidance of potentially harmful substances. Current topics will also be discussed including fetal origins of adult disease, pregnancy after weight loss surgery, environmental bisphosphonates, and glycemic index diets.