The Randall cycle is primarily driven by the NAD to NADH ratio within mitochondria, which signals the cell's redox state and regulates pyruvate conversion to acetyl-CoA.

“what drives the render cycle effect when you oxidizing primarily fats the this what I call the master conductor redox modulator which is the NAD to the n8h ratio specifically the intra mitochondrial one drops and basically the NAD to the nadh equation which kind of signals how oxidized versus how reduced you are right metabolically that ratio basically turns out to be the primary regulator of where the pyruvite dehydrogenase will accept pyruvate and convert into acetyl COA and then continue with the Krebs cycle in the electron transport chain or not”