The University of North Carolina study found that fussy babies get introduced to solid foods earlier than laid-back infants, which may lead to consumption of excess calories and childhood obesity.
Based on standardised growth curves, the study found that one-third of nine-month-olds and one-third of two-year-olds in the US are overweight for their height.
“Moms are definitely giving kids a lot more to eat than just breast milk, which is the recommended thing up to three months,” said lead author Barbara Goldman, a psychologist at the Frank Porter Graham Child Development Institute at the University of North Carolina.
“What we’re finding is that even if they’re not breast feeding and they’re doing formula, they’re doing formula plus other things very early,” Goldman told LiveScience.
For their study, the researchers recruited more than 200 first-time moms and visited the families every three months from the time the infants were three months old until they were 12 months old. A final visit took place when the babies were 18 months old.
It was found that about 70 per cent of babies got at least some breast milk in their first month of life, and a total of 20 per cent got breast milk exclusively. However, those numbers dropped off quickly, with just 25 per cent being breast-fed by three months of age.
The American Association of Pediatrics recommends that babies should be breast-fed exclusively until four months of age, and six months if possible. It also recommends that solid foods be introduced after four months.
