"Get fit" what exactly does that mean to you? Does that mean packing on the lean muscle mass like body builder or are you looking to take off that last 10 pounds of stubborn fat or are you 20, 30, 50 pounds overweight? Exercise does not walk alone it walks with diet. For instance you may be able to do 100 crunches however if you eat a bit of carbs 20-30 minutes prior to your work out you will have the energy to do those crunches properly. The subject of exercise and nutrition is extensive, there are no single "fast" methods that fit all people. Your goals, your body type, your ability to put in time all factor into this. Without knowing how fit you are now, what kind of routine you are able to get into say at home weight set or at a gym? Are you even planning on weight lifting or are you seeking cardio type exercises? If it is weight lifting then its not how much weight you need to lif or how many times to lift a bar, you need to balance out the two numbers. i.e. endurance and definition is done through light weight and high reps. high reps means around 20. The weight depends on how much you can lift 20 times slowly to where you reach fatigue to where you can not lift that bar of weight a 21st time. Mass building is low reps (like 3-5) with more weight - again how much weight depends on you. Again its a slow push and lowering of the bar to where your muscle fatigues on the 3-5 th rep to where you can't lift it again. Then we need to talk sets, and the rest between sets... Fast is not usually a thing to talk about when it comes to fitness, unless you are into some sort of racing like running, swimming, etc. Weight-lifting is not a racing sport BTW>>> :) EDIT: Addition: As per our commemnt. Then you need to work toward mass building (converting fat to muscle actually) and think cardio program. I would start of with a high weight low rep set routine hitting the major muscle groups (full body -start with the strongest muscles first like thighs and biceps, work down to weakest muscles last)Monday, Wednesday and Friday. Then on Tuesday and Thursday take up a cardio like jogging, biking, or swimming. Start of with that for about a month then add to the cardio say Saturdays. After three months switch to endurance training - lower the weight increase the rep to 15-20 3 sets, split the routine to working upper body Monday, Wednesday and Friday, working the lower body Tuesday, Thursday and Sat. Say weight train morning and cardio evenings. Mind endurance training is similar to cardio and can take the place of cardio. Diet: Reduce added fat (ie stop fried foods, reduce fatty foods like bacon, margarine, etc) Reduce added sugar - switch to an artificial sweetener in coffee, eat "adult" non sugar added cereals, etc. 20 to 30 minutes before a workout (cardio and weight training) eat a carb, to increase the natural conversion of carb to sugar in your blood stream - sugars are the bodies energy source. Post workout eat high protein. In fact eat more protein all the time unless your last work out was more than two weeks ago. Muscles build during the time away from the weight set - all the weights do is shred the muscle to promote growth of muscle tissue - muscle tissue needs proteins and other stuff to grow. Add a daily one a day supplement, get plenty of sleep and drink plenty of water and clear liquids (like grape juice, apple juice, blah).