The song’s lyrical theme was one which recurred in several songs on the album: the idea of two parts creating a whole, often allegories for Lennon’s then-faltering marriage to Yoko Ono. Interestingly, it was Ono who suggested to Lennon that he sing the song outside his normal range.
Well, that’s just a concept of life, you know. How to live life. It was Yoko’s idea for me to sing it all falsetto.
All We Are Saying, David Sheff
In the studio Lennon recorded a guide vocal without the falsetto – it was later released on the 1998 box set John Lennon Anthology. That version, which omitted Something Different’s backing vocals but brought Ken Ascher’s keyboards to the fore, was arguably more affecting in its sense of melancholy.
On the final version melancholy had largely turned to saccharine, and Lennon’s lyrics (“’cause I’m the fish and you’re the sea/’cause I’m the apple and you’re the tree”) appeared tired and trite. Lennon had composed more honest and touching tributes to Ono, and despite being one of Mind Games’ stronger melodies, ‘One Day (At A Time)’ failed to convey any real sense of emotional conviction.
Elton John evidently thought differently, however, and recorded the song as the b-side to his 1974 cover of The Beatles’ ‘Lucy In The Sky With Diamonds’. Although Lennon was credited with vocals and guitar on the recording of ‘One Day (At A Time)’, his contribution appears to be inaudible.