I have been on Atkins for the last 6 weeks and am feeling and doing great (if I may say so). But, I haven't done any real excercise or workout since I began. I have heard stories of 'gaining weight' because ? muscle weighs more than fat, etc. that I am afraid I might stall my progress. Anyone else have these concerns? Am I out in left field on this and should start excercising again? Appreciate your thoughts!