Why has my hunger levels gone up so much after beginning to work out?

I recent started in mid-June to work out daily during the summer after promising my dad that I would. I do 15 minutes of cardio and at least 45 minutes of weights and machines. Lately I noticed that I get hungry much more frequently than usual. I feel the need to eat something every two or three hours. Normally I don't eat for hours at time (unless I'm being a fat *** and just munching on snacks) and don't often feel hungry. I am Muslim so my body is kind of trained not to eat a lot or eat frequently because of Ramadan. I want to know if my metabolism increasing or am I just eating more than I really should? Also I'm 17 and weight about 166 pounds. I haven't lose any weight but my family and friends have told me I've slimmed down a bit since starting. I'm not very fat, just mildly overweight, and I'm around 5'6. I eat in my usual fashion, which honestly is not very healthy, and am not on a diet. I'd really appreciate helpful answers about this.