Moms-to-be typically enjoy full license to chow down on food during pregnancy. After all, you’re eating for two, and when else are you going to have that freedom? Although it’s important not to gain too much weight to avoid problems like hypertension and gestational diabetes, experts say that in the interest of your child — rather than your physique — you should not unduly restrict calories.

A study of baboons, published in the journal Proceedings of the National Academy of Sciences, found that dieting during pregnancy might actually stunt fetal brain development. Calorie restriction also is linked to low birth weight and other developmental delays.

Researchers allowed one group of baboons to eat to their heart’s content, while the other group was fed thirty percent less — an amount similar to a human mother’s diet if she restricts or loses calories, or has morning sickness.

The scientists found that cells divided more slowly in unborn baboon babies in the dieting group, and fewer neuron connections formed in the brain.

Researchers believe the results are relevant to humans and emphasized that early pregnancy is a crucial time for fetal development.

The study also raised concerns for the nutritional needs of teenage moms, who themselves are still growing and need supplemental nutrition from food. Older moms, too, need to make sure they eat a healthy, nutrient-rich diet.

How much is enough? Experts say aim for two to four pounds of weight gain during the first trimester, which comes out to about one hundred extra calories a day. During the second and third trimesters, go for a pound a week. Avoid too much fat, which can contribute to childhood obesity, and make sure to nosh on food rich calcium, iron, fiber and folic acid.

When eating for two, remember to keep baby’s brain in mind, too. Go ahead and have some ice cream — just not too much.