Ha! Yes! It’s tough to power a study that much, though.
You may not recall when I was futzing around with the ‘day of MCT upregulation’ based on Green’s paper. In that paper they saw MATERIAL upregulation of monocarboxylate & glucose transporters w/in hours of training stimulus. So you could at least hypothesize that adaptation could happen in days…but I think that hypothesis goes of the rails if you instead first train the subjects for ~20 weeks and then do the Green MCT/GLUT upregulation protocol.
https://journals.physiology.org/doi/full/10.1152/ajpregu.00699.2007