Eating healthy and making good food choices when getting a quick bite can be a pretty tough proposition. You're hungry, it's late, you're on the road, the only thing open is Long John Silver's—we've all been there, and we hear you.

But you're about to get an ally, or at least a new piece of information to make better decisions. To help people make better (that is, healthier) selections on restaurant menus, government guidelines first proposed in the Affordable Care Act in 2010 have mandated that restaurants add a calorie count next to items on their menu by May 2018.

The only question: Do the calorie counts make a difference?

To find out whether adding the calorie information does affect people’s food decisions, researchers from the University of Sydney in Australia looked at more than 200 studies on the effects on consumers and retailers. The researchers found that putting calorie info on menus led people, on average, to reduce their consumption by 27 calories per meal, and influenced restaurants to serve 15 fewer calories per meal. Women, in particular, took notice of the calorie counts—they ate 60 fewer calories per meal. The healthiest-minded among us? Overweight people, who ate 83 fewer calories per meal.

“With more and more food dollars spent on meals purchased outside the home, anything we can do to educate consumers, and make them a bit more aware of their choices, is a good start,” said Natalina Zlatevska, Ph.D., a professor at the University of Technology Sydney. “In the same way that corporate or financial disclosure changes behavior, here we see the disclosure effect changing the food environment. We know that retailers are adjusting so there is the possibility of a combined effect. That is where I think bigger change will probably happen.”

In the meantime, eat healthier with your list of nutritionist-selected meals at 50 popular U.S. fast-food chains.