And, from what I understand, if you "cheat" on Keto, and instantly gain 3 pounds from it, it's not really fat that you have gained that quickly, but your shrunken fat cells filling up with water again. (the first weight you lose on Keto is truly water weight)
I never could figure out how one dish of ice cream could cause me to gain 2 lbs, but now I know, or at least I think I do. And that kind of weight should come off soon by getting back to strict Keto for a few days.
Whether or not this way of eating is for you kind of depends on your relationship with food. And how much of a carb addict you are. And how deeply ingrained your "healthy food" lessons are. This "9 servings of grain per day" dogma is pretty much the opposite of how you will eat on Keto. This way of eating is not for everyone.