Here’s an interesting article that explains why training for a marathon is not necessarily the best prescription for weight
It turns out that while running can burn a lot of calories (about 100 – 150 per mile) it also makes you more hungry. Most runners tend to overcompensate eating many more calories than they burn. I know this happens to me.
The more I learn, the more convinced I become that exercise is not nearly enough for weight loss. If you want to lose weight, eat less. Sure, you should exercise (by doing a little joggling) but don’t expect exercise to melt the pounds off. It won’t.I remember during my 50 mile joggling effort I actually gained 3 pounds!
On the plus side, there is no evidence that being overweight is necessarily unhealthy. In fact, overweight runners can be just as fit as skinnier people. So keep running even if you aren’t losing weight. It will make you feel better no matter what your weight is.