If I recall right from the book, it's the part about burning more fat when running at a low heart rate that she disproved. I'll have to find that book and go through it again. I think she was saying it makes no difference what the heart rate is.lol you implying the rest is false?
Even now, I don't see why running at a low heart rate makes you burn more fat than carbs, in an absolute or relative sense. And by 'you' I refer to a healthy euthyroid (normal thyroid) person with good blood sugar control. But if a person has poor glucose uptake to his cells, he would always have to rely on fatty oxidation as glucose oxidation would be insufficient for his energy needs for running. Still, what he burns would still be independent of his heart rate.