If you are interested in losing a lot of weight, in a hurry, but in a safe way that will allow you keep it off, then you should check out some body weight calisthenics. These are likely the best exercise to lose weight fast. The reason they work so well is that they work large groups of muscles, instead of isolating them like people do at the gym. A second reason they are so good is that after doing them for a couple weeks, you’ll be doing quite a bit of reps. And high rep, low weight exercises are fantastic for building lean, strong muscle mass, which skyrockets your metabolism to astronomical levels. If you start doing body weight calisthenics, then you’ll be burning fat in no time.