Possible Clues:

• Supporter assisting in what Oliver wanted?
• Additional plateful
• Of course, this is just more of what Oliver was looking for
• Every boxer has this dietary supplement
• One may have this at Christmas dinner -- a boxer usually has one
• More, at a meal
• Ali had what Oliver wanted?
• A boxer normally has one, even if not hungry
• Extra plateful
• That's more like it, of course