Kentucky Fried Chicken showed the most improvement in a 14-year study regarding the nutritional quality of fast food.
Researchers in Minnesota analyzed data from menus of eight restaurants, including KFC, McDonalds, and Burger King.
Based on the healthy eating index, the overall quality improved by points.
KFC saw the most improvement with a nine point increase.
High fat and high salt foods can lead to diet-related chronic diseases.
More than 25 percent of American adults eat fast food two or more times a week.