Because his new movie role in "The Beach" calls for him to strut around in swim trunks -- and because he's put on a few pounds this past year -- Leonardo DiCaprio is not only working out with a personal trainer but is drinking a protein powder favored by baseball record-holder Mark McGwire, reports New York's Daily News. The paper blames Leo's weight gain on his being laid up by knee surgery in August and his "nightcrawler's regular diet of vodka and cranberry juice." As a result, he's "been less than excited about taking his shirt off." "The Beach" starts shooting in January.