I can tell you this from experience diets don’t work because the word ‘diet’ means for a short period of time, or for a period of time. Diets work for a short period of time, but then once you start eating again, you start gaining weight like crazy.
In my opinion, and I know it sounds like an old cliche The only way to go is to change your eating Lifestyle !
The first problem ( for me ) is that my mum was a good cook and I grew to love Steak and kidney Pie, Suet Dumplings and Fish and Chips and I still salivate at the thought of them.
The second problem is that I have had periods in my life of extreme physical activity and I put much of my weight gain down to continuing to eat very large portions when now having an almost sedentary life style.
I am not a person who enjoys going to the Gym but for example when I was a diving Instructor on the Great Barrier Reef I enjoyed the huge physical effort that went with the job.
So my conclusion is that I must change my eating habits, by restricting the number of calories I eat. Eat Less but Eat well !