The World Health Organization study found they may over-estimate how quickly babies should put on weight.
This may have caused unnecessary concern about for breastfed babies, who gain weight more slowly.
The research was dicussed at a meeting organised by the London School of Hygiene and Tropical Medicine and the International Obesity Task Force.
The child development growth charts in widspread use are largely based on studies of formula fed children from more than 20 years ago.
Formula fed babies tend to put weight on faster than their breastfed counterparts.
The latest WHO study, of 8,440 children from six countries, found that target weights for two and three-year-olds were 15% to 20% too high.
The researchers say the current overfeeding of babies could explain in part why this generation of adults is the fattest ever.
The WHO will release new growth charts based on breast-fed babies at the end of the year.