"Age Isn't Everything" is the title used on the film when released instead of its original title, "Life in the Food Chain." In fact, a line at the end of the movie relates to the original title better.
The story of a college graduate who embarks on a career of something other than his original plan and becomes old in the process is somewhat abstract. He became a businessman instead of an astronaut and this caused an aging process to kick in. Also, he obtained a New York Jewish pattern of speech which did not exist until he began aging. This seemed out of place but carried the old man persona. The comedy plot wasn't really funny. Resolution at the end was tied in but, again, abstract.
A good reminder to follow your goals in life, but not a high rated film. Apparently the reason for its limited release, even on video.