Returning to running after a two year break (young kids, work etc etc) and have started back in training currently clocking up 17 miles a week. I'm 6'2" and weigh 16 and a half stone, trying to loose weight but failing miserably (4lbs in three weeks depsite diet). I desperately want to get back to my good times when I could run a marathon in 3:42 (2004) but feel like an aerodynamic slug. At the risk of sounding pathetic- Now 40 and feeling generally cr*p and like a zeppelin despite my new running regime - where am I going wrong? or am I being too impatient?