Ah, yes, the Warburg effect. The real question is whether cancer cells cannot use anything but glucose due to faulty mitochondria, or if they're using glucose preferentially for a different reason.

What Lewis Cantley writes about the interaction between insulin and phosphoinositide 3-kinase (PI3K) - which he discovered in '84 - makes the best sense to me.

In short, the issue is not high sugar, but high insulin, which explains why insulin resistance (which often results in T2D) is a cancer risk - and why "going ketogenic" (either low carb or fasting) makes chemo more effective.

I'm not a bio guy, but the whole process of how glucose transporters work - and how people like Cantley figured it out - is beyond fascinating.