Why has Paul Lieberstein (Toby) appeared so thin all of a sudden on The Office?

In the just-concluded season of The Office (season 7), Paul Lieberstein, who plays Toby Flenderson, looks much thinner than he did in the past. This seems to be a sudden change. For instance, in the last episode of the previous season (season 6), he looks his usual self. In past seasons he’s had a medium build, not heavy but not especially skinny.

I’ve tried some obvious Google searches [why is toby paul lieberstein skinny, has toby paul lieberstein lost weight], but all I find are other people asking the question with no one answering, or spammy sites.