You are defenitly not eating enough for your height and weight. I'm a girl, 120lbs, 5'2 and I eat more than you. You are probably slowing down your metabolisme by not eating enough. Also, if you've been doing the same workout for a while now, change it up a little. HIIT every day + weights is crazy! 3 cardio sessions and 3 weights sessions should be enough. Maybe you are overtraining.
The belly flab will be the last to go. Just continue lifting, do
moderate cardio (2-3 times a week) on different days than lifting preferably and re-evaluate your diet because for a 160lbs guy 1500 cals is a starvation diet!
edit: It would also do you alot of good to have a cheat day to reset your metabolism.