I lost the bulk (heh) of my weight over 40. It wasn't easy by any means, but it was easier than it was when I tried in my 20s & 30s, because I was more prepared mentally in my 40s to face reality
There's a huge difference between having to lose 20 lbs from middle aged spread, and the metric $hit ton of weight I had to lose LOL it was clearly a mental problem, not a slow metabolism. I did the work I needed to do in my mind, let go of things I couldn't seem to in my 20s (the notion that I'd be Christie Brinkly if I lost 30 lbs) etc., got myself sorted out and the weight came off easier than I ever thought it would
so it all depends on your perspective I guess, what's easier or harder. Off is Off in my mind
