OBJECTIVE. We aimed to provide information that can be used as a guide to clinicians when advising breastfeeding mothers on normal lactation with regard to the frequency and volume of breastfeedings and the fat content of breast milk.METHODS. Mothers (71) of infants who were 1 to 6 months of age and exclusively breastfeeding on demand test-weighed their infants before and after every breastfeeding from each breast for 24 to 26 hours and collected small milk samples from each breast each time the infant was weighed.RESULTS. Infants breastfed 11 Ϯ 3 times in 24 hours (range: 6 -18), and a breastfeeding was 76.0 Ϯ 12.6 g (range: 0 -240 g), which was 67.3 Ϯ 7.8% (range: 0 -100%) of the volume of milk that was available in the breast at the beginning of the breastfeeding. Left and right breasts rarely produced the same volume of milk. The volume of milk consumed by the infant at each breastfeeding depended on whether the breast that was being suckled was the more or less productive breast, whether the breastfeeding was unpaired, or whether it was the first or second breast of paired breastfeedings; the time of day; and whether the infant breastfed during the night or not. Night breastfeedings were common and made an important contribution to the total milk intake. The fat content of the milk was 41.1 Ϯ 7.8 g/L (range: 22.3-61.6 g/L) and was independent of breastfeeding frequency. There was no relationship between the number of breastfeedings per day and the 24-hour milk production of the mothers.CONCLUSIONS. Breastfed infants should be encouraged to feed on demand, day and night, rather than conform to an average that may not be appropriate for the mother-infant dyad. REASTFEEDING MOTHERS SHOULD be made aware of the variability of milk volumes per breastfeeding, the frequencies of breastfeedings, and the distribution of milk intake by day and by night of healthy breastfed infants. 1 Mothers among the !Kung hunter-gatherers have been observed to breastfeed 4 times every hour during the day and at least once at night. 2 In contrast, Cadogan,3 in his essay to the Governors of the Foundling Hospital (London, United Kingdom) in 1748 recommended that infants be suckled only 4 times a day and not at night, because he considered the night feeding to result in breastfed infants' becoming "over fat and bloated." Relaxation of the concept of scheduled breastfeeding was first strongly promoted by Wickes 4 in 1953 and subsequently advocated by community support groups such as La Leche League and the Australian Breastfeeding Association that were at the vanguard of the movement back to breastfeeding in the early 1970s in Western societies. As a result, infants were breastfed more frequently both by day and by night. It now is recognized that breast milk provides the optimal nutrition for infants, and current recommendations to mothers are that infants be breastfed "on demand" (according to their appetite) exclusively for the first 6 months of life. 5,6 Bangladeshi infants have been found to consume half their daily milk ...