I agree, 25 miles a day sounds doubtful. I do not think that anyone could keep weight on while walking 25 miles a day. At the same time you dont relly lose that much weight if your walk if barely a stroll. Someone mentioned that 25 miles is marathon? I think a marathon is 26 miles right? Anyway, runner know they can't run a marathon everyday, it works backwards for them, they increase their chance of injury and burn out. I don't even think it is possible to walk 25 miles everyday, at moderately fast pace(especially in an 8 hour work day) and still not lose any weight. Did you ever try a pedometer? With an accurate measure of your stride you will see how much you truely walk in a day.