I have been trying to loose weight for two months now, mainly by changing my diet. I haven't really lost weight, so I want to incorporate some exercise into my routine. Would bike riding for a few miles a few times a week help me at all? If so, how much would it help? BTW- I weight about 166 and I am a 17 year old girl. I am looking to loose 45-50 pounds (not necessarily fast though) and how fast could I loose weight doing this? Please help!