The watchdog group, the Center for Science in the Public Interest, named Long John Silver's "Big Catch" meal as the worst meal in America.
Though Subway is marketed as a healthy fast food option, adolescents ate virtually the same amount of calories as they did at McDonald's, one study found.
Children who are overweight have a greater risk of heart disease, diabetes and premature death.
Among people who died of strokes, heart attacks or related conditions, 40 percent of them were defined as premature; 84 percent of these deaths were linked to salt.
New research suggests an overwhelming 75 percent of the world's population consumes twice the daily recommended amount of salt.