Has anyone lost say , 3 stones of more and kept it off?
Yes, my OH did. He was overweight since childhood but when he was in his early 30's he did a lifestyle change which resulted in a "permanent" weight loss of 4 stones, which he's kept off for the 21 years of our married life.
He had a sedentary job (sat at office), a 2 hourly daily commute sat in the car, did no exercise and just binged on crisps, chocolates etc all day (an addiction started in childhood when he first discovered the primary school tuck-shop!). Luckily, he never smoked and never liked any alcohol, so food was his only vice (sadly still is!).
We worked together on changing his "trigger points". A lot of his eating was from stopping off at garages on his commute to buy pies, chocolates, crisps etc to eat on the commute. He'd tried not stopping, but like I say, it was an addictive habit. So we worked to get him a more local job in our own town, so he didn't have the time or opportunity to stop off and stuff himself on his journey. That was a massive success in itself and the weight started to come off.
Then we started the exercise. We just started going for walks, bought ourselves a couple of bikes to do some easy cycling, took up learning to play golf. Nothing excessive, no gyms or marathons, just made sure that we included various forms of light exercise at least twice a week. The weight kept coming off.
He lost 2 or 3 stones within maybe 6 months of the life change and in the years since then, he maybe loses a pound or so every month or two, so very gradual, but at least it's all downwards.
He doesn't (and never has) do "diets". He eats normally the same as the rest of the household, probably not too healthily as he likes his chips, processed foods, etc., and turns his nose up at the suggestion of salads or veg! But, because he doesn't binge anymore and doesn't really eat snacks between meals, he can get away with it, and the regular light exercise which we still do stops the weight coming back on at least.
I'm sure he could lose another stone or two pretty easily if he'd cut back on the chips & processed foods and increased the fruit/veg, but he's happy as he is for now, and like I say, we're happy that there's still an occasional pound or so reduction even on what I think is a poor diet.
For him, the change was all about a change in attitude and lifestyle, we identified his trigger points and problem areas and dealt with them, rather than going down the road of fad diets.