sounding slogans, reduced fat, whole grain, that means healier, right? not necessarily. >> the packages all have claims. the claims are often misleading. >> reporter: this yale scientist created nuval, a nut trigs rating system that cuts through the marketing machine. >> it's gps for the food supply. >> reporter: it ranks food from 1 to 100, weighing unhealthy things like transfat against nutrients like fiber. >> almost everything in the produce aisle is between 90 and 100. we have reduced fat jif peanut butter way 7 and regular with a 20. >> reporter: so higher fat is better for you here? >> not because it's higher fat. the reduced fat version is considerably higher in sodium and sugar. >> reporter: raisin bran. this what i eight growing up.