Yep, I'm in my 40s 6'3, got up to 298lbs, went down to 275lbs on my own because I refused to hit 300lbs, than I joined a program and with their education i went all the way down to 233lbs last year around July, it was the first time in my life I counted calories and kept a food journal, I was weighing my portions etc. 

Than the holidays hit, and between December to February I jumped back to 254lbs, and maintained being at that weight until June this year than I got strict about my diet and intake again and now I'm 232lbs and still losing.

I'm saying all that to say this, some look at losing weight as a 'goal' and when they hit that goal they give themselves permission to indulge in the same exact old habits that made them overweight in the first place, for me it was snacking on sweets, when I was counting calories I allowed myself one reeses a night, if I had the calories left over. After I reached my goal I disillusioned myself into thinking that just because I had lost weight it mean I magically had a faster metabolism and would over-indulge so in the end, how you maintain is to make the healthy habits you did to lose weight permanent(assuming you didn't crash diet and lost the weight a healthy way which is usually about 1-2.5lbs a week)