Hi amaliayosa,
I don't think you gain weight back that quickly. I lost 24 pounds on this diet this fall and quit coming in after christmas due to money being tight (I should have just made sacrifices because I could be my goal weight by now!) anyways, I ate healthy afterwards, lower carb -- but certainly not perfectly...and certainly not the packets...when I came back last week to start over, I had only regained 4 pounds. That made me even more confident that this is the right diet...that I am not just losing water weight, etc...that the changes are for real.. quitting any other diet that suddenly would have resulted in a major gain
best of luck! My best tip is plan nothing big for this week incase the caffeine withdrawals and change in eating makes you tired. I have been eating this way for 2 days now and last night I was so tired I went to bed by 9....however, after this week, you are good to go and feel more energetic...any major diet change can affect your energy levels at first