I tried all sorts of diet clubs decades ago - on some regimes I put on weight or saw no loss at all - I was told that I was doing it wrong. I was told to go away at several of them.
The only way I could maintain my weight was reducing the carbs - to lose weight I needed to eat low carb and more fat.
It was never popular and I was told many times that it was dangerous, even that I should be forced to eat properly - but once Dr Atkins 'New Diet Revolution' was available I felt vindicated and managed to continue low carb for a long time, until my cholesterol suddenly became a problem.
I want to be at least 100 lb down from my heaviest weight, maybe 120, but most of all I want normal blood glucose levels.
For me it is just a batter of eating omelettes and salads - no hardship this weather - but you would need to adjust your insulin levels down to cope - and change the amount of carbs little by little if you chose to go the low carb route. It is, however, a permanent change if you want to maintain the weightloss then you can't return to a 'normal' diet as that is what got you into the fix in the first place.