A combination of becoming a True Believer and a lack of omega 3's, protein, b vitamins, and sat. fat. Paleos do it too, but at least their D levels tend to be better.
And True Believer is a disease that effects everyone; christians, atheists, blacks, whites, men, women, libertarians, communists, liberals, republicans, anarchists, vegans, paleos, etc.
“The whole concept of a macronutrient, like that of a calorie, is determining our language game in such a way that the conversation is not making sense." - Dr. Kurt Harris