That's a lot of hiking.  Not to mention you know she'd just eat the burned calories back rather than lose the weight. Burning off that many calories will make most people hungry. Now a normal person who needed to drop some p  3e98  ounds would think "Awesome, if I'm hungry that means my body's burning off the fat!" Someone with so little impulse control that they get fat in the first place will think "Oh, I'm sure I can give myself a treat since I burned off so many calories!"