Hey Jay453!
I experienced the same thing....I kept my weight off for 8 years. I went from 272 lbs and a size 22 to my lowest weight of 139 and a size 2. I maintained that for about 6 years then hit 50 years old and oh boy has it been a struggle! I was very disciplined for all of those years and then got a little lax and gained 27 lbs and 3 pants sizes. I've started working on getting back on track, made some changes and am down 13 lbs and a pant size. Have 14 more to go to be back at my 145 and size 2-4!
I had to find new things that worked since things that I did pre 50 doesn't work anymore!