I’ve lost ten stone and kept it off for two years. I did (and still do) low carb. But I have to have a blow out every so often or I wouldn’t be able to do it. I really thought it would be easy to keep it off once I’d lost it - but it’s still a struggle.
Then I wrote a book about it and it’s on Amazon. Well, I say a book, it’s more of a leaflet… It’s sold enough copies to keep me driving lorries 
I had visions of me having to turn down jobs due to having book signings…
Must admit to being worried going back to driving lorries and getting back into bad habits, but you have to put the effort into being organised, taking stuff with you rather than having to choose from the dire offerings in service areas. Exercise is the easy bit… put your trainers on and move!