My doctor told me to stop having intimate dinners for four. Unless there are three other people.

Welles turns a doctor’s advice into a self-deprecating joke about overeating and indulgence. The phrase “intimate dinners for four” implies a small, cozy gathering, but the punchline reveals the “four” are not guests—he is effectively eating enough for four people. By adding “Unless there are three other people,” he flips the meaning back to its literal sense, highlighting the absurdity of his appetite and the social veneer that can disguise excess. The humor depends on misdirection and on Welles’s public persona as a larger-than-life bon vivant, using wit to acknowledge (and deflect) concerns about health and self-control.