According to Dr Johnson's book, The Fat Switch, the Inuit's macro diet was 50% fat, 35% protein, and 15% glycogen from the animals they ate. Average intake was 3000 calories.
Here's the problem with a vlc diet. It can increase your uric acid production through the breakdown of proteins (muscle or diet). Exercising excessively will also raise uric acid levels through the breakdown of muscle. Too low a body fat % will also up uric acid production. Hibernating animals that didn't put on enough fat for winter will come out of hibernation in a last ditch effort to find food once their fat supplies have exhausted. The trigger that wakes them up is high uric acid.
Would I be putting a grain-feed cow on a fad diet if I took it out of the feedlot and put it on pasture eating the grass nature intended?