Craig Bates once mentioned that he had felt much higher levels of sex-drive than was normal when he was very ill, whereas when he regained his health, his sex-drive was more normal, but still higher than when on a SAD diet. I had the same experience. His idea, which I agree with, was that when men are ill, their sex-drive goes up because the body anticipates it's going to die so boosts the sex-drive in order to ensure the propagation of the genes - however, when women are ill, becoming pregnant is such a burden on the body that their sex-drive goes right down in order to prevent them from becoming pregnant as pregnancy is a waste of time if the body isn't going to survive more than 9+ months.