He should have a serious talk with Charles Barkley and ask Charles what the biggest regret of his NBA career is. Charles has a similar build and played at least 75 games in 6/8 seasons with Philly (3 times top-5 MVP voting, including a runner up to MJ), but he was actually in shape for most of that. Then he got the trade he wanted at age 28, played 76 games (won MVP) and reached the Finals his 1st season in PHO, then got fat and happy and never played more than 71 games in a season the rest of his career. At age 29. Never saw another Finals or top-5 MVP voting again
If Charles is honest with Zion I have to presume he'd touch on the importance of conditioning/diet