The objective of maternal diet is provision of sufficient nutrients to maintain mother and fetus in good health, to support an adequate flow of breast milk without detriment to maternal nutritional reserves, and to maintain maternal health between pregnancies.1 Daily dietary recommendations for Central American women are presented in Table 1.2 The recommended dietary pattern for pregnant women is different from that for nonpregnant women, and the values are set at the upper level of the distribution curve of requirements. Most individuals consuming them would, in theory, be amply nourished. Although the consumption of more energy than is actually spent is undesirable, the recommended caloric intake for pregnant women is set to provide for storage of about 36,000 kilocalories during pregnancy as adipose tissue reserves. This is because "a safe level of energy intake is a basic requirement to insure satisfactory nutrition for the fetus and breast-fed infant."
Arroyave G. Nutrition in Pregnancy in Central America and Panama. Am J Dis Child. 1975;129(4):427–430. doi:10.1001/archpedi.1975.02120410015007