I applied that during chemo, starting 72 hours before and ending 48 hours after the chemo infusion, there are clinical trials also using it in combination with chemo, the principle is, in a nutshell, when you are fasting healthy cells go in "hibernation" while cancer cells cannot do that, so the chemo is hitting more cancer cells and less healthy ones
stemcell.keck.usc.edu/usc-s...
But anyway, cycles of this diet seem to be good and easier to deal with than an actual complete fasting