I did read part of it, and I partially agree with him.
I think taste and smell play a huge role in whether something is needed by the body/beneficial. For example there are studies showing mice deprived of water and electrolytes, once given the option to drink plain water or water with electrolytes, choose water with electrolytes. There's other factors too, like a person who is tired is more likely to feel sleepy. Essentially instincts, when 'listened' to, give ques for what the body needs/benefits most from.
However I partially disagree with him, because in a way I feel like he may have 'set restrictions' for certain foods that perhaps shouldn't have been restricted. Not cooked food, but perhaps salt, occasionally sprouted grains. There's also the factor of food scarcity and every food not always being available. I believe there is room for improvement in his diet, but that there is strong premise for his concepts making sense.
In this regard, I believe there is something to eating instinctively, and also living instinctively.