It just occurred to me. What did they use to cause cancer in the first place? Remember Collin Campbell's mice experiment with casein and cancer? He used aflatoxin to cause cancer. Evcen though he used mice, even though use used aflatoxin, even though he used casein, he declared meat caused cancer in humans. It's the same thing here, even though they used mice, even though they obviously used something other than fat to cause cancer, and even though they likely used some hydrogenated veggy oil, they imply (or at least that's what we are lead to believe) that animal fat causes cancer in humans.

Consider Feinman's work again. He used a ketogenic diet to shrink tumors. Doesn't tell us what caused cancer in the first place, but it certainly suggests that, a) fat does not cause it, and b) carbs likely allow or cause continued growth (after initial cause, which may or may not still be present).

Then we gotta ask, what is the thing that allows or causes growth? Is it fuel? Maybe. It's useful to look at other examples of growth. Child's growth - growth hormone. Fat tissue growth - insulin. Breast growth - estrogen and prolactin. Muscle growth - testosterone (it's more complicated than that, but it illustrates the point). Then we got growth distribution like the differences between men and women - primarily sex hormones testosterone and estrogen. Does fuel enter the equation at any point? Yes, but only insofar as we restrict fuel will it affect growth, even then there's still gonna be growth but at the expense of other tissues, i.e. fat tissue grows but we get tired and other tissues shrink, etc.

Feinman thinks it's all about the insulin. I agree. Cancer cells apparently have 10x the number of insulin receptors. I wonder why. I wonder why a ketogenic diet shrinks tumors, but not really, it's obvious - there's much less insulin cuz there's no carbs to stimulate it. Nevermind the fuel, cancer cells would get it anyway if there was ample insulin, but there isn't. Imagine a sort of diabetic type 1 cancer. Tons of glucose, but zero insulin. I wonder if there'd be any growth.

To summarize.

Cancer is initially caused by something that can be different than the growth agent. Cancer grows according to hormonal signaling. Fat (i.e. animal fat) does not cause cancer in humans, nor does it cause cancer to grow in humans.