New to MFP- Need to loose atleast 100 lbs

Hello everyone, I an new to MFP, I have heard of the success and freedom of this application and think its wonderful so far. I have been on the log for a week starting tomorrow and find it very eye opening to how horrible I really was eating even when I thought I was eating healthier!!! I have my small goals set and motivated so far, weighing in later today hopefully I can see the first few lbs come off. I would love to hear how some people have excercised the weight off at my size without killing themselves. I am 250 lbs right now, help...!