Using treadmill to beat munchies

I've started getting up on the treadmill when I get the munchies. ::snicker:: It works pretty good, I get the munchies and so I walk on the treadmill until I am too tired to go up to the front of the house to grab junk food to munch on. Not sure if it will work in the long run, but I had reasonable results with that technique today when I was trying to avoid munching on stuff. My goal is to walk a little on the treadmill each day until I can build up to where I am walking a half an hour on it. Right now it is ticking me off and making that hard (I can walk a couple hours outside no problem) because the tread keeps sliding too much to the side as I walk. It snags up under the side rail things and I have to stop to put it back in place. Adjustments to the tension are not helping because the darned thing id messed up. Really driving me insane and making me seriously contemplate a new treadmill.