<P> The average breastfed baby doubles its birth weight in 5--6 months . By one year, a typical breastfed baby weighs about 2 - 1 / 2 times its birth weight . At one year, breastfed babies tend to be leaner than formula - fed babies, which improves long - run health . </P> <P> The Davis Area Research on Lactation, Infant Nutrition and Growth (DARLING) study reported that breastfed and formula - fed groups had similar weight gain during the first 3 months, but the breastfed babies began to drop below the median beginning at 6 to 8 months and were significantly lower weight than the formula - fed group between 6 and 18 months . Length gain and head circumference values were similar between groups, suggesting that the breastfed babies were leaner . </P> <P> Breast milk contains several anti-infective factors such as bile salt stimulated lipase (protecting against amoebic infections) and lactoferrin (which binds to iron and inhibits the growth of intestinal bacteria). </P> <P> Exclusive breastfeeding till six months of age helps to protect an infant from gastrointestinal infections in both developing and industrialized countries . The risk of death due to diarrhea and other infections increases when babies are either partially breastfed or not breastfed at all . Infants who are exclusively breastfed for the first six months are less likely to die of gastrointestinal infections than infants who switched from exclusive to partial breastfeeding at three to four months . </P>

How long does the average woman breast feed