A few years ago I wrote about the new WHO growth charts, which use the growth of breastfed babies as the norm.
Research has shown that formula fed babies grow differently than breastfed babies. The most obvious difference is that formula fed babies do not slow down in growth the way breastfed babies do between 4 and 6 months. But most health care providers in the U.S. still use growth charts that use either formula fed growth, or a mixed formula/breastfed growth (whatever that is) as the norm. More information on those charts is here.
What this means is that for some time, breastfed babies have looked "underweight" when they've been growing normally. That has led to supplementation and early weaning. And children at risk of overweight have been less likely to identified as such. The key here is that these are not charts "for breastfed babies." They're charts representing normal infant growth, to be used with all babies.
It's been three years since the WHO released its growth charts based on breastfed growth, but it's taking a while for the charts to become accepted and used.
That's why I think it's very exciting that the U.K. will be adopting charts based largely on the WHO charts as of May 1st. The National Health Service website says, "[The charts] will replace current charts that were based on predominately formula fed babies. The new charts will help parents and healthcare professionals identify children at risk of obesity at an early age."