It’s not as impressive as some of the other projects mentioned here, but there was a one-year hiatus during the filming of Cast Away to allow Tom Hanks to lose all (and more) of the weight he had gained for the first part of the movie. His beard and tan were earned honestly during that time as well.
I chose the second option after my new fridge got too friendly with my MIL’s phone. Nothing against her, but I didn’t want to give it the chance to do that with a stranger.