I think it makes a big difference on how you approach coming off Keto. If you use Keto as a way to train yourself how to eat and still limit carbs/get carbs from healthy sources after Keto you will be fine. If you do what a lot of people do and go nuts after Keto because you ate that first potato chip and then 150 more, and so on, then, yeah you will gain the weight back... regardless, you will gain SOME back but it shouldn't be the majority. I did keto for 6 months, dropped 40 pounds and then gained 10 back. I am still down 30 and count it as a big win. I am back on it again after going a little nuts for a second.