I am trying to locate a film that was shown on tv back in the 70's as
part of the Kukla, Fran, and Ollie show.  The movie was about an
overweight child and how he was treated by others.  I think it may
have been a Japanese film, perhaps with subtitles, but I'm not sure. 
The theme is definitely about an overweight child and how he is
treated by others.

Hello.

The film was "Skinny and Fatty."

See this newsgroup message archived by Google Groups:

"> Wasn't Skinny and Fatty a Japanese film? I saw the movie on the CBS Saturday
> afternoon kid show,Kukla Fran and Ollie in the early 1970's.
> Mike Shields
Yes, it was a Japanese film. I remember seeing it on Kukla, Fran and Ollie as
well."
http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&c2coff=1&selm=34DF4C55.37C91632%40tcsi.com


From the "CBS Children's Film Festival with Kukla, Fran and Ollie" web page: 

"Skinny and Fatty         Japan, 1959, 55 minutes
A chubby boy from a wealthy family befriends a lean and poorer
classmate in this sentimental children's story from 1959. ?Skinny?
excels at school, sports, and making friends.  He tries to help
?Fatty?, who has a talent for antagonizing the other children, but
finds he is only fighting his friend?s battles for him.  He tries to
prod Fatty into thinking and acting on his own.  Available on VHS"
http://users.ultinet.net/~kfo/cbs.html


Order a VHS copy from nextgen-video.com"
http://www.nextgen-video.com/skinny.htm


The original Japanese title was apparently "Chibideka monogatari"
(1958).  See the Internet Movie Database:
http://www.imdb.com/title/tt0407643/plotsummary

------
search strategy:
google groups: movie "fat kid" japanese
googe: "skinny * fatty"

I hope this helps.