It sounds like a simple enough plan. Go run for several miles and the fat will melt off no problem. It does work for awhile, but you eventually get to a point where it will slow to a halt. For instance, you have been running 5 miles a day but not losing any weight. What in the world is going on? There are probably several things going on. One major factor is that the more you run, the more efficient you become at it. Great for running, but not so great for fat loss. Your body will get to a point where it burns less calories to do the same amount of work it used to. Getting to the point where you can run 5 miles was probably a great milestone at one time, but if you keep doing the same mileage in the same amount of time you’re not making progress. You need to run farther or run faster. This goes for any exercise you do. If you are doing the same speed, reps, weight, etc... every time you are spinning your wheels. That's the bad part about exercise, you have to keep trying! I know that's tough. This also leads to another factor and that is overeating. Some runners will assume they can eat and drink whatever they want because they have put in so many miles. Another contributing factor can be skipping out on your strength training workouts to focus solely on your cardiovascular training. Strength training will not only help keep you injury free, but it will also help tremendously with fat loss. Strength training workouts will not burn the same amount of calories DURING the exercise session as cardiovascular training, but you will continue to burn calories for hours AFTER your workout is completed. This effect is called the afterburn and we will talk more about that later. Also, the more lean muscle mass your body has on it, the more calories you can burn sitting around watching the Jersey Shore. It’s t-shirt time! While it is possible to lose muscle from doing too much cardio, it has to be an excessive amount to do so. You need to pick a lane. It is hard to lose fat and to do long distance training. I speak from experience. It made me skinny fat. When I was running a lot, I got to where I weighed about 185 pounds, which is a good weight but I was a soft 185 pounds. I weigh around 200-205 now, hardly ever do long distance running, and my body fat is much lower now. If you punch me in the stomach you will hurt your hand. If you're my 5 year old son anyway. So that's the lesson for the day. Pick a lane. Are you concerned with performance or how your body looks? Two different approaches.