Here is my take on the whole rapid weight gain. It is impossible to gain 5 pounds of fat in a week unless you are eating 2500 calories a day
above your maintenance calories. Now you ask - well why does it happen? What I think is this - when you are running a calorie deficit - even a slight one that most people would be in during maintenance - I think that the process of using fat stores is naturally dehydrating. When you have a "cheat" day and I never use that term - who are you cheating? I mean, it always comes down to a choice... but I digress
I think what you see when you bounce 5 pounds and you
know for a fact that you were only over maintenance by say 3500 calories in a week is water weight fluctuation.
I base that on research into the mechanics of losing weight as well as my own personal observation. If I bounce up 3 or 4 pounds 1 week - I almost always have an off setting large loss the next week. I no more really lost 5 pounds in a week where I was running a 1000 calorie a day calorie deficit than I gained 5 pounds by eating 500 a day over maintenance.
The only real thing you can track is average weight over time. Then the fluctuations of day to day water retention are washed out. If your average is moving down, you are running a deficit. If it is moving up, you are eating too much - if it is staying the same - you are hitting maintenance.
As Dennis Miller used to say - Of course, that is just my opinion, I could be wrong.
I wish you all the best. Howie - great to see you are doing OK after your surgery. Good to see you back posting.