Expectant women who eat for two could be endangering their health for decades to come, doctors have said.
Those that put on too much weight are more than four times as likely to be obese in 20 years time then those who follow the advice of their doctor.
The health risks from obesity include diabetes, heart disease, stroke, infertility, depression and some cancers. It's estimated that being obese can take up to nine years off your life.
The advice now is just to eat the right amount for you, rather than the traditional advice of eating for two to ensure the baby is born a healthy weight.
An Australian study focussed on 2,000 women during their pregnancy, and then two decades later. 41 gained too much. The results showed that these women were 4.5 times more likely to be classed as obese in the future.
Traditionally, women have been advised that 26lb is the maximum amount they should put on during pregnancy. New draft guidelines suggest they only need an extra 200 calories a day during the last three months of pregnancy.