It would limit the amount available, but not cut off the glucose.
Mike, I read somewhere (but it's not in the Seyfried article -- T-bone's #3, where I thought it was) that ketone bodies inhibit glycolytic enzymes.
Normal cells generate ATP by both glycolysis (in the cell cytoplasm) and respiration (in mitochondria).
Tumor cells, according to these articles, have dysfunctional mitochondria and they generate most of their ATP from glycolysis. Even if glucose levels are adequate to provide energy for tumor cells due to liver gluconeogenesis, the presence of ketone bodies, (if they inhibit glycolytic enzymes), would diminish the tumor cells ability to produce ATP that way.
So tumor cells would be screwed by a ketogeniic diet. Their mitochondria don't work, and their glycolysis enzymes are inhibited by the ketone bodies. They can't generate enough ATP to maintain their cell membrane integrity, so they swell up and die.
At least that's the theory. I've had some people tell me this is too simplistic, and probably it is. But I'd like to see a head-to-head study of cancer patients treated with usual therapy vs usual therapy plus a ketogenic diet.
I wonder if Atkins foundation would fund one. I'm sure the concept would scare the hell out of the regular funding agencies and of course the drug industry. Especially if they had to stop the study early due to the marked superiority of the KD!!