The eating less slows your metabolism isn't exactly true.  Over a long term of eating less than you burn, it will slow a little bit during the calorie deprivation, but it will speed right back up once you get back to your nutritional requirements.  It isn't some magical decrease that will last for eternity.  The dipshits on Biggest Loser regain the weight because they go back to eating like the pigs they are.  They whine about damaged metabolism just so they can deflect the blame away from their own poor eating habits.