I often wonder metabolic switching between e.g. fat vs carbs as energy sources would be a good way to force cells to perform some acrobatics and die if they have a distribution of mutations that make them metabolically inflexible. Might be easy to test in a lab with radiation and different feeding cycles for cells/mice, look for rates of cancer development. May be negligible, hard to say.
There are many claims regarding "autophagy" out there, some say it helps the body to remove cancerous cells. But there are cancer types that can circumvent or even take advantage of this. As with everything it depends and is no silver bullet.
I mean it might not be. There might be long term consequences.