Ikki Kajiwara and Tetsuya Chiba's 1968 Ashita no Joe (Tomorrow's Joe) was a gritty boxing manga that prefigured Rocky. It followed the travails of Joe Yabuki, an orphan from Tokyo's post-war slum, and the hardships he endures to make it as a boxer. One of the series' pivotal tragedies involves dropping weight for boxing, so, with partially self aware tackiness, Joe is now promoting weight control soda.
Kirin Mets Cola is a carbonated "fat busting health drink" with the claim that "the drink contains an indigestible form dextrin sometimes used as a fiber supplement, which restricts the body’s ability to absorb fat while eating."
It launches in Japan this week, targeted at a men over 30, and Joe has been hired on as spokesperson. In an ad, coach Danpei looks on in dismay as Joe eats pizza and hamburgers, but, Joe assures his trainer that the diet is alright, because he's drinking the fat blocking Kirin Mets Cola.