Checked the glycemic index of cherries and most GI lists rank them the lowest of all fruits. Grapefruit is next up on the list (second lowest). Strawberries, plums, peaches, and nectarines are down there as well.
I wonder if cherries could be equally subsituted for grapefruit on a precontest diet due to their low GI rank. Yeah, yeah, grapefruits are thermogenic, but I bet cherries could be eaten as substitution. At least in the summer when they're in season!

Yes, you can sub. Just don't change. There's a difference, especially the final 4 weeks.

Frank

Email me a few cherries!!!