Babies fed with enriched bottle milk are more likely to be obese by the age of five, a British study found.
The study shows faster weight gain in infancy can put babies at risk from heart disease to diabetes in later life.
It found healthy babies given formula milk enriched with protein, vitamins and other nutrients had 22 per cent to 38 per cent more body fat than those fed standard bottle milk.
The researchers believe they took in more calories and experienced weight gain at a crucial stage in growth, reports the Daily Mail.
They said previous research suggested that 20 per cent of adult obesity may be caused by over-nutrition or other early excessive weight gain in infancy, reports the American Journal of Clinical Nutrition.
Mothers were once advised to give enriched milk to underweight babies if they were not breastfeeding. But they are now told not to 'fatten up' their babies unless they are premature.
Study leader Atul Singhal, from the MRC Childhood Nutrition Research Centre at University College London, said: "This study supports the case in the general population for breastfeeding since it is harder to overfeed a breast-fed baby."
In the study, body fat mass in five to eight-year-olds was 22 percent to 38 percent greater in those given nutrient-enriched milk as babies than those who had standard formula.
The scientists said previous research suggested 20 percent of adult obesity may be caused by over-nutrition or other early excessive weight gain in infancy.
Breastfeeding is known to be associated with slower weight gain while infant formula increases the production of fat cells, fuelling weight gain throughout childhood.