What type of cardio shoud i do?

i have alot of fat but have been losing weight gradually at about 1-2 pounds a week, i have been running alot of long distance like 4 miles every day rest on saterdays and have long runs on sunday i lift 3 times a week, anyway i have been hearing alot about HIIT being superior for fat loss and that i shouldnt do long distance anymore but why not do both? i live by a levi with a very steep ramp cant i just do my long distance and do sprints up the ramp and jog/walk down for like 10-20 mins ? would this speed up fat loss or burn me out