Who would be heavyweight champ if weights, supplements, and modern training methods were banned?

Assume for a moment that the boxing commissions somehow decide (and manage) to ban all training methods popularized in the last 80 years or so. So from now on, boxers are limited to roadwork, bagwork, sparring, medicine balls, steak and potato dinners with veggies, and the like. Basically they're only allowed to train with the kind of stuff that good ol' Nat Fleischer would have prescribed in the 1930s.

No weights (even though Turpin and Jeffries admittedly used them to a degree.) No creatine, protein shakes, or other supplements. No fancy current-day periodization schemes, or any of the rest of it. Certainly none of Hatfield's weird ergonometer voodoo that he used with Holyfield, or Shilstone's diet plans. Those are right out.

Who rules the current heavyweight scene under these admittedly odd conditions and rules? And why?

(* DISCLAIMER: This is purely a hypothetical.)