I have been trying to find this old Japanese cartoon, that I watched in mid to late 80s (but no idea as to age). I don't remember a lot of the story line, but I do remember the graphics were along the same line as dragonball z (coloring and drawing, not action sequences) and it is about a little boy who is friends with/related to a large man (I think he is suppose to be a sumo wrestler). The main thing I remember is that the man is going to be in some kind of contest and has to lose weight so the boy gets him to get into a "sweat box" with just his head sticking out, and the boy keeps feeding him rice balls. If anyone can help, please let me know, I have been looking for this movie (I do not think it was a TV show). Thank you!