Metabolsim might be slower but I think motivation is higher to actually live a healthier lifestyle. Can't count on youth making the argument "yes I'm fat but perfectly healthy". The blood pressuere and cholesterol numbers start creeping into borderline....
Also, personally I was able to put together a plan that worked for me by reflecting on a lifetime of trying to lose weight. I knew what worked for me and what didn't. I had the confidence to shrug off "musts" that didn't work for me.