‘Eating for two’ during pregnancy is a dangerous myth, study suggests

While it’s easy to believe that pregnancy warrants an extra slice of cake at tea time, the old adage that women can “eat for two” when they’re expecting poses health risks to the child and mother-to-be, new research suggests.

Published in the journal Diabetologia, the study shows that if a woman gains too much or too little weight during pregnancy, it can have adverse effects on their child.

According to the analysis of 905 mother-child pairs, which was conducted in Hong Kong, gaining too much weight could put your offspring at an increased risk of insulin resistance and high blood pressure.

The child may also be more predisposed to macrosomia, whereby a newborn is significantly larger than average.

Plus, they may have a higher than normal BMI - all of which researchers say could lead to further cardiometabolic risks down the line.

Participants’ weight gain was measured against the Institute of Medicine’s (IOM) guidelines and researchers found that pregnant women who’d gained more weight than the IOM recommended amount had children with higher blood pressure and poorer blood sugar control than those who gained weight within the recommended range.

Interestingly, the same adverse effects were true for women who actually gained less weight than the recommended amount.

On average, the weight change from pre-pregnancy to delivery was 15kg for women taking part in the study, with 41 per cent having gained weight exceeding the recommended range and 17 per cent having gained weight below, with those in the former group more likely to be young and have a higher BMI.

Meanwhile, 42 per cent gained weight within the recommended levels.

While lead researcher Professor Wing Hung Tam doesn’t think the results mean we should revert back to the practice of regular weigh-ins for pregnant women - which the NHS stopped doing in the early 1990s - he said it’s crucial to educate them about the implications of pregnancy weight gain and to dismiss the “eating for two” theory.

“What’s more important is that ‘eating for two’ could be harmful,” he tells The Independent.

“A pregnancy requires an extra 300 kcal per day. What a pregnant mother needs is a balanced diet meeting such requirements with adequate micronutrients.

“They also need to have moderate exercise to avoid putting up excessive weight gain.”

Though the study focused on highlighting the adverse effects that excess pregnancy weight gain can have on children, Hung Tam explains that it also poses a series of health risks to the mother, such as a higher risk of gestational diabetes mellitus - a condition where the mother has higher than normal glucose levels.

"These findings have important implications for both prevention and treatment," the study's authors conclude.

"There is a need for greater awareness and monitoring of weight gain during pregnancy."