I would offer food, even if they're in shed. My boy ate like a champion when he was in shed, but to be fair the Ball I had years ago refused food at the drop of a hat, so YMMV.

Still, the worst that can happen if you offer food is that they refuse until their shed is complete.

Also...some pythons fast for months, so long as your critter is in good health, I doubt a two-week stint of not eating will hurt.