I am just finishing up day 4 of a very looooooong 3 week liquid diet of Optifast. I am finding it not too bad as far as not eating goes. I would say it is only mildly uncomfortable. I managed to sit through turkey dinner with my family, sipping my shake, with only mild jealousy. That being said, the last 2 days I have been having some unbelievable mood swings. Think a major case of PMS. I honestly don't know if my poor sweet husband will last those 3 weeks. To those who have been on the liquid diet, did you experience mood swings, and did they ever subside?