A new study suggests that eating potatoes may actually help to decrease body weight gain.

A team of researchers at McGill University fed mice an “obesity-inducing diet” along with a polyphenol-rich extract made from lots of Irish potatoes (about 30 per daily dose). The mice who didn’t get the potato serum gained “about 16” grams, while the ones who did only gained seven.

The results so shocked the researchers they repeated the experiment with “potatoes grown in another season.”

The potato compound may help prevent obesity and type 2 diabetes, according to researchers.

While this may seem like good news to all the potato lovers out there, lead author Stan Kubow warns that no one should take this as a sign to eat 30 potatoes a day. However, the study says that “a simple potato extract may limit weight gain from a diet that is high in fat and refined carbohydrates.”

The benefits of the extract, which the research team hopes to patent, are due to its high concentration of polyphenols.

The discovery may also shed light on the so-called “French paradox” — how do French people eat the way they do and still remain so skinny?

“In the famous French diet, considered to be very healthy, potatoes – not red wine – are the primary source of polyphenols,” says Kubow.