I've lost and gained the same 2-4 stone about four or five times. The net result is that, despite six years of on/off dieting, I weighed the same at the beginning of this year as I did when I started dieting! Worse, I'm sure I do genuinely eat less now, meaning either age or a messed-up metabolism caused by yo-yo dieting has made it even harder!
All of the diets I've done have worked. What has failed me is, often slowly, bad habits have crept back in until, truthfully, I've got to the point where I've eaten what I want, when I want, while doing little or no exercise for a sustained period of a few months, without weighing myself.
Sometimes I rationalise it. I'll have a takeaway, perhaps the first for months after losing weight, then behave for a week and see no change on the scales. This becomes, in my head, 'I can have a takeaway every now and again' and as a result the takeaway happens once a week. This gradually becomes twice a week for a few months, with the odd chocolate bar thrown in and a few nights of lager followed by morning fry ups. I'll then step on the scales and notice I've put on half a stone. I'll think 'that's not bad, I've lost three or four before now, that'll come off quickly' and make no change, continuing on a downward spiral, without weighing. These unhelpful thoughts result in rapid weight gain and I'm back to where I started before I know it!
We've all heard the advice 'it's not a diet, it's a lifestyle change'. It's annoying and at times feels patronising when people point it out, but it's true. Long term changes, sustainable habits. That's surely the way forward.
I'll let you know when I've lost three stone (again)!
Good luck, and hope you lose it for good this time.