This is a hotly debated topic. If you get the leanest ground turkey, it will cut back on fat and calories, but ground turkey tends to be slightly higher in cholesterol compared to ground beef. So it depends on what you are trying to cut back on. Lean ground turkey is also going to lack slightly in flavor and will be drier. In a recipe like this, that doesn't matter as much because there is so many other components adding so much flavor.