I think that those of us coming to PB from a life of SAD have a fat deficiency just like a vitamin D deficiency that takes longer than any vitamin deficiency to correct. I have been primal for a year and still feel the need for a lot of fat... maybe more than I would need if I had eaten a high fat diet all along. I think it can take years for your body to recover from a fat deficiency. When we are vitamin D deficient a doctor will usually prescribe a high dose ...say 50,000 IU for 3 months. For those of us who are fat deficient I think we may need an extra high fat diet for a long period of time to restore and rebuild all of our cells. And I'm sure most of the population is fat deficient.
I came to primal after a Weston A Price diet, so I had had a some time to get more dietary fat. But I clearly remember when I first added raw grass-fed,full fat milk to my diet, I was obsessed with it for a while. I would be at work daydreaming about getting home to have glasses of milk - I was drinking 2 gallons a week on my own . I am sure it was my body going bonkers over getting that fat after so much time without it.
Using low lectin/nightshade free primal to control autoimmune arthritis. (And lost 50 lbs along the way )