Not a fruit of Islam
Malcolm, would eat once a day,
Until late in his time with the nation, he would drink water, but also drank tea to help function due to his grueling schedule he kept
Ali did not necessarily do the one meal, but he got himself a Muslim chef to cook the meals he could eat, i do remember him doing ramadan during his training period,
But you can read up on that from this book by Manning’s Marble
Malcolm X a life of reinvention
The book touches on Malcolm and Ali, and Ali’s introduction into the nation, and his split with Malcolm