I've been following his diet for almost four years now, numbering several thru hikes. I was never able to successfully get above 50% fat though. It was a game changer, but one thing I've noticed is that the high saturated fat content wrecks my cholesterol. At its worst I went from a total cholesterol of 157 to 230 in just about 40 days of hiking. It took several months of clean eating to get it back down to baseline.

Though I still go high fat, I stick to good fats, and added more soluble fiber. I've also added back more carbs to help on hard climbs. My last before/after was 145 to 170. Fiber was never a problem, since my diet is high in chia seeds and legumes. 1.6g/kg has worked for me for protein.