That's the theory behind it, higher resistance to catabolic stress. I would say that some authorities dispute the presence of obesity paradox but, last I looked, the data was compelling.
May be not a bad idea, considering what chemo does to people's body mass. That said, fuck cancer.
@Jay585: no, didn't mean to imply that. I've seen keto diet do crazy things to people's cholesterol but I don't have anything to say that it translates into some acute risk.