Babies are piling on the pounds because their mothers are watching television while feeding them, researchers fear.
They say that the 'technology trap' may be distracting new mothers and stopping them from noticing when their children have had enough milk.
Having one eye on the television or texting on their phones while feeding could also be making it harder for mother and child to bond.
The US researchers said that just as TV dinners led adults to eat without thinking, mothers may be guilty of 'mindless feeding'.
With obesity cutting up to nine years off life, experts say today's youngsters could be the first generation to die at an earlier age than their parents.
The researchers questioned 41 women with young babies about what they did during bottle feeds. Some 83 per cent admitted to multi-tasking, with watching TV the most common activity. Other distractions included playing on computers and phones.
Multi-tasking was more common among older mothers and those who had more than one child, it was reported in the journal Early Human Development.
The researchers from California Polytechnic University found that babies tended to consume more formula when their mother was distracted.
They said women with big families may find it particularly hard to avoid distractions but, "given the ubiquity of technological and other distractors in today's society", needed to be educated on the dangers of failing to focus on feeding.
The researchers concluded: "Previous research with older children and adults suggests that eating while distracted - 'mindless eating' - increases the risk of overeating.
"Thus it is possible that mothers who engage in 'mindless feeding' are similarly placing their infants at higher risk for over-feeding than mothers who are not distracted."
Clare Byam-Cook, a breastfeeding adviser, said that while a breast-fed baby would stop when full, a bottle-fed one may drink a little bit more - especially if the mother was distracted and pushed the teat back toward the child's mouth.
If this occurred regularly, this is likely to lead to weight gain.
"I am not saying it will cause obesity all over the country but any kind of eating without full attention can result in eating more than needed," said Mrs Byam-Cook.
- Daily Mail