The evidence regarding its effect on obesity is inconclusive

In many developed countries childhood overweight and obesity have reached epidemic proportions.1 Moreover, the sequelae of obesity are now seen in children.2 Fortunately efforts are being made to understand the causes of overweight and obesity, and the part played by breast feeding is also being studied. The short term benefits of breast feeding are not doubted, and it is the safest, most economical, and most convenient way to promote infant health and nutrition on a global scale.3 Increasing evidence4^–8 shows that having been breast fed may have longer term benefits, including prevention of obesity; but this evidence is uncertain.910 Two articles in this issue evaluate whether having been breast fed protects against later obesity.1112 Neither finds evidence to say that it does. Why the contradictory findings? Although there is no easy answer to this question, the explanation may be that the studies examining early infant nutrition and later obesity are observational and therefore subject to several caveats.

For obvious reasons it …