Based on the dietary energy supply per person per d and a minimum energy requirement of 1.4 X basal metabolic rate (BMR), it is estimated that 11-32% of adults in developing countries were undernourished (Food and Agriculture Organization, 1990). Even if adequate amounts of food are available, unequal food distribution favouring men over women and cultural taboos may restrict food intake of women. Since they are usually engaged in productive activities which entail a substantial energy expenditure (McGuire & Popkin, 1989), it is likely that the majority of undernourished adults in developing countries are women. Indeed, most publications from developing countries report low energy intakes of women, particularly during pregnancy and lactation. The high incidence of low birth weight and growth faltering at an early age have been attributed to maternal undernutrition. While there is no disagreement about the adverse effects of acute and severe energy deficits on the outcome of pregnancy and lactation (Stein et al. 1975;Prentice, 1980), no consensus has yet been reached on the relationship between maternal nutrition and reproductive performance in communities having marginal energy intakes either seasonally or chronically (Rush, 1983; National Academy of Sciences, 1990Sciences, , 1991. Maternal depletion over the course of numerous reproduction cycles is an often hypothesized but little measured phenomenon (Merchant et al. 1990a,b).Results of recent studies indicate that, in industrialized countries, healthy pregnant and lactating women who can eat to appetite do not increase their dietary energy intake to the degree recommended (World Health Organization, 1985), with no resulting impairment of their reproductive function (Whitehead et al. 1981;Durnin, 1987; National Academy of Sciences, 1990;van Raaij et al. 1991). The longitudinal study on energy requirements of apparently healthy pregnant women which included three developing countries (The Philippines, Thailand, The Gambia) did not show a consistent pattern of reproductive physiology (Durnin, 1987). The main problem lies in the concept of 'apparently healthy'. On the other hand, the extra energy requirement during lactation in developing countries may approach the dietary recommendation (Frigerio et aI. 1991;Madhavapeddi & Rao, 1992).The calculated energy requirements in pregnancy and lactation (World Health Organization, 1985) or observed energy intakes of apparently healthy women in industrialized countries bear little relationship to the needs of many Third World women who are poorly nourished to start with. For practical purposes it is more relevant to assess at which level of maternal energy status, child and maternal outcomes of reproduction are compromised.Studies in The Gambia show that seasonal fluctuations in energy intake were reflected in concomitant weight changes of pregnant and lactating women, mean birth weight and the quantity and quality of breast milk were reduced, the incidence of low birth weight increased (Prentice, 1980). The improve...