If he was very overweight when you got him, and now he is crated maybe more than he is used to, remember he still probably has lots of fat that his body is drawing on. What I'd do, is, whatever that meal was that you gave him and he ate, mix more of that up for now, and give him about 1/4 or maybe 1/2 the amount. He may eat a smaller amount if offered, rather than a large bowlful. If he is healthy, active, bright eyed, I don't think I'd be too panicked, though it is very different. Did you get him checked out with the vet? Does he look like he is still overweight, or is he looking thin? He may be just regulating his diet himself, because maybe his activity level is gone down with the crate time?
Meanwhile... have you got room for one human? Boy, I'd be delighted if I could make myself eat just three times or so in three weeks !!! Yes !!!
