So what gives? The authors credit the state’s laws that set strict limits on the sale of snack foods in schools. Also, in 2009, the state banned the sale of soda and other sweetened beverages (think sports drinks) in high schools.

“The evidence is entirely consistent with what the laws were designed to do,” says University of Illinois researcher Dan Taber.

So, can 158 fewer calories a day have any meaningful impact on the complex obesity problem?

The daily swing of a 158 calories may sound trivial, but over the course of the year this can really add up, explains Dave Grotto, RD, president and founder of Chicago nutritional counseling firm, Nutrition Housecall LLC. “That can mean 15 pounds a year – gained or lost- depending on which side of the calorie equation you are on.”