Feeding babies milk enriched with nutrients to promote faster weight gain in infancy makes them fatter later in life, researchers suggest.

Body fat mass in five to eight-year-olds was 22 per cent to 38 per cent greater in those who were given nutrient-enriched milk as babies than those who had standard formula, according to a team based at University College London's Institute of Child Health.

Previous studies have shown a link between over-nutrition in childhood and overweight adults in animals, but this is the first demonstration in humans when other factors, such as the size of mothers, are ruled out.

The scientists said the findings, published online in the American Journal of Clinical Nutrition, have important public health implications as Britain tackles the problem of obesity. They confirm previous estimates that more than 20 per cent of adult obesity may be caused by over-nutrition or other early excessive weight gain in infancy.

Researchers looked at two randomised, controlled, double blind studies – where neither they nor the mothers knew which kind of milk they were assigned – involving newborn babies.

Professor Atul Singhal, who led the research, said: "This study robustly demonstrates a link between early nutrition and having more fat in later life in humans. Immediately, it raises the issue about the best way to feed those children small for gestational age, which should now be evaluated in the light of all current evidence. In public health terms, it supports the case in the general population for breastfeeding – since it is harder to overfeed a breastfed baby."