Energy and protein supplementation was most often associated with weight gain of women, and often targeted pregnant women with suboptimal weight. For pregnant women, energy and protein supplementation modestly increased maternal weight (86–90). Other maternal outcomes were not frequently reported, and were often secondary objectives of protein-energy supplementation interventions (33, 88). Many studies reported on infant health outcomes, including reductions in low birth weight and preterm births (19, 89–91). Adequate energy and protein intake was also relevant for interventions targeting the prevention of excessive gestational weight gain of overweight and obese pregnant women. These interventions restricted dietary energy intake of overweight women during pregnancy and resulted in reduced excess weight gain during pregnancy but had no impact on pregnancy-related hypertension and pre-eclampsia (19, 88).
Young adults. Teen girls and young women usually need more calories than when they were younger, to support their growing and developing bodies. After about age 25, a woman’s resting metabolism (the number of calories her body needs to sustain itself at rest) goes down. To maintain a healthy weight after age 25, women need to gradually reduce their calories and increase their physical activity.
Iron: Iron, too, remains a critical nutrient. Adult women between the ages of 19 and 50 need 18 mg a day. Pregnant women should shoot for 27 mg a day. “The volume of blood almost doubles when women are pregnant, which dramatically increases the demand for iron,” Schwartz tells WebMD. After delivery, lactating women need far less iron, only about 9 mg, because they are no longer menstruating. But as soon as women stop breast-feeding, they should return to 18 mg a day.

The delivery of nutrition education reached women across all life stages and through many platforms. Many nutrition education studies that targeted pregnant and lactating mothers reported on women's outcomes, but the primary focus of many of these studies was child health outcomes (13, 14, 19, 21, 24, 28); few studies focused on dietary outcomes and behaviors of pregnant and lactating women themselves (17, 20, 23). There were some studies evaluating the impact of nutrition education on the practices and outcomes of school-age children and adolescent girls (15, 18, 27, 29, 34), as well as older women (16, 22, 25, 30). Many of the nutrition education interventions were clinic-based (17–20, 23, 24). However, nutrition education was also delivered through community-based programs, including home visits (16, 21), community centers (15, 16, 20, 21), worksites (25), and schools (25, 27, 30, 34).