The supplementation program of the community nutrition project (PNC) launched by the Senegalese Government in order to protect the most vulnerable groups (children and women) was evaluated. Using a stable isotope (deuterium), we assessed the effect of the PNC on breastmilk output, mother's body composition, and baby's growth at three months of lactation. Breastmilk triglycerides, lactose, protein, and zinc were also determined. Mothers who were supplemented more than 60 days during pregnancy showed a significant increase in fat-free mass as compared to those who were supplemented for less than 30 days (p = .03). Breastmilk output was not influenced by the supplementation, but breastmilk lactose, total protein, and zinc contents increased significantly (p < .01) in the supplemented mothers. Growth of the babies of the supplemented mothers was better than that of those whose mothers were not supplemented. It was concluded that the food supplementation had beneficial effects on both mothers' and babies' nutritional status depending on the onset of the supplementation.