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Leaner Adult Bodies

Breastfed infants become leaner adults. New research is discovering that leanness is associated with general health and well-being and with a lower risk of such diseases as heart disease, stroke, and diabetes. Studies have shown that children who were breastfed are less likely to be obese during adolescence, and that longer periods of breastfeeding greatly reduce the risk of being overweight later in childhood. Since overweight children are more likely to become overweight adults, preventing obesity in childhood is important. Lean means having just the right amount of body fat for an individual's body type. In 1992 the DARLING (Davis Area Research on Lactation, Infant Nutrition, and Growth) study from the University of California at Davis compared the growth patterns of healthy breastfed and formula-fed infants and found that breastfed infants were leaner at one year of age than their formula-fed counterparts. Even plump breastfed babies gradually lose a lot of their adorable baby fat and eventually wind up leaner than their formula-fed peers.

Why this difference? The amount of fat and calories in formula is about the same as in breast milk. The answer lies both in the type of fat and in the feeding method itself. As we discussed before, breast-milk fats, which are high in omega-3 fatty acids, are healthier fats. Also, breastfeeding gives infants the opportunity to control their fat intake themselves. The fat content of breast milk changes during a feeding to meet the needs of baby. If baby is simply thirsty or just needs some comfort sucking as a pick-me-up, baby sucks briefly for the foremilk, or “low-fat milk” that is stored right behind the nipple. If your baby is particularly hungry, baby sucks longer, stimulates mother's milk-ejection reflex, and gets the higher-fat hindmilk. Contrast this with the formula feeders. Regardless of whether baby is hungry, thirsty, or just needs to suck for comfort, he gets the same amount of fat whether he wants it or not.

Also, the fat content of mother's milk changes as the baby grows. The older infant needs fewer calories per pound of body weight than does the younger one, so by a wonderful quirk of nature, the level of fat in mother's milk gradually decreases to lower levels in the second half of the first year.

The satiety factor. Breastfed babies take smaller meals and eat more slowly. Eating patterns established in infancy reduce the tendency toward overeating later in life. Also, the high-fat milk that the baby receives toward the end of the feeding gives him a feeling of fullness. This and a satiety-producing hormone in the infant called cholecystokinin (CCK) condition the satisfied infant to stop eating. The breastfed baby himself controls how much he eats. You can't urge him to finish up the last 1/2 ounce at the breast the way a parent might when giving a bottle. A breastfed baby learns to trust his own signals about how much he needs to eat and when.

Better Eyes

Not only does breast milk build brighter brains and healthier bodies, it's valuable to baby's vision, too. Studies comparing breastfed and formula-fed infants show that visual development (in particular visual acuity) is better in breastfed babies. This finding is particularly noticeable in premature infants. Again, the smart fat DHA may be one of the reasons. DHA is one of the prime structural components of the retina of the eye. As with all tissues, the better you feed it, the better it grows and functions. So the better you feed the retina, the better the vision - another reason why breastfed babies have a healthier “outlook” on life.

© 2000 by Martha Sears, R.N., and William Sears, M.D.

Tags: Breastfeeding

About the Author

Martha Sears is a registered nurse, childbirth educator, and breastfeeding consultant.

About the Author

William Sears, M.D., received his pediatric training at Harvard Medical School's Children's Hospital and Toronto's Hospital for Sick Children. He has practiced as a pediatrician for more than thirty years.