According to a new study, bottle-fed babies are more likely to develop unnaturally large appetites and become obese later on in life. The study by Atul Singhal of the Institute of Child Health in London showed 20 per cent of adult obesity is caused by over-feeding in infancy. This is because bottle-fed babies aren’t limited in their intake of milk, unlike breastfed babies who have to work hard to get it. Singhal says the message parents should take home is not to over-feed their child—even if it’s born small at birth. “In public-health terms, it supports the case in the general population for breastfeeding—as it is harder to overfeed a breastfed baby,” says Singhal.