The best you can do is offset it with lots of stretching and cardio. Cardio will chew through muscle, especially if you don't provide it with enough post-workout building material.
Soooo, try doing like 30 min or so of stretching every morning along after a light warmup, and if you're up to it, a brisk walk/jog at some point during the day. While you're on this manual labour gig, maybe consider going vegetarian or vegan for a while, or at least cut back lots on the protein and fat and up your carb intake. Also, try not to eat for an hour or two after you've stopped working.
Mina.
