Why you gain weight if you eat more than your cut

This would explain why I am losing and gaining the same 5lbs every week! By the weekend, I lose around 5 pounds, and then I have a cheat day (usually Saturday) and by Monday (don't see a change on Sunday) I am back up to where I was the previous Monday. Then I spend the rest of the week losing them. So goes the roller coaster ride! Everyone that I could ask, that were in the "know", said it was "probably" water weight gain. But, they weren't sure and were only guessing. But, this explanation reveals what is most likely going on.

Thanks for the explanation.

Be careful with a cheat day. If you're not tracking it, and your deficit isn't steep enough during the week to cover it, you can actually undo everything you worked for during the week. I recommend doing something a bit more moderate... if you cut 500 calories/day (i.e. your goal is to lose 1 lb/week), if you feel you need a "cheat" day, just bump up your goal on one day of each week by 500 calories. In essence, you'll be in a deficit 5 days out of 6 and you'll lose just under 1 lb/week. If you go all out, instead, and have a cheat day on which you eat 4000-5000 calories (not hard to do if you eat at a restaurant - burger platter, drinks etc.) you can possibly leave yourself with just a 500-1000 calorie deficit for the week - not enough to see any significant weight loss within a matter of weeks.

So go with a calculated "refeed" day to maintenance, or just keep tracking and choose to go over here and there. If you track everything, at least you know where you stand. If you just say, "It's cheat day so I don't log anything," you will have no idea how big your deficit is or isn't or whether you're undoing all the effort you're putting in all week.