Some people do have 4 packs for the first 3 days or so to ease themselves in, I didnt when i first started but I did the first week back on plan after chrsitmas. I found it easier to have 4 after being used to eating so regularly at christmas, but try not to do it for too long. Also, make sure they are soups/shakes as having too many bars in 1 day might affect ketosis as they have slightly higher carb content so I'm told. Good luck!