Ok so I've friends who do slimming world, I see the food they post on ig and believe me I can understand why they keep losing and gaining the same 3lb. I wouldn't be able to lose weight with some of the huge meals they eat and as for the cheats......
Weight loss is simple, it's not easy but it is simple. All you need to do is eat fewer Calories than you burn. There are a multitude of ways of creating this deficit, some far more complicated than others.
4 years ago I weighed 289lb (almost 21stone), I've been maintaining in the 148-152lb range for over 2 years and just decided I'd like to drop another 10lb.
But I didn't diet, instead I made a lot of little changes that added up to a massive lifestyle change that means now I eat a lot less and move a lot more. No foods are banned or synned, if I want to eat something and it fits in my Calorie allowance then I do.
I have also gone from being unable to walk across a room to running marathons. I train 6 days a week, and I train hard. Yes I will always have issues with food, but have mostly learnt to turn to exercise rather than the giant box of chocolates.
I try to have a healthy lifestyle rather than diet.
Eat less than you burn - to lose weight
Strength train to preserve muscle and strengthen bones (especially important for us ladies), to look better after the weight loss
Cardio for heart/lung/mental health and to give a few more Calories to eat.
Oh and contrary to what some SW fans say, muscle does not weigh more than fat, a pound is a pound. But muscle is more dense than fat, so a pound of muscle is smaller than a pound of fat. Also you won't put much (if any) muscle on in a deficit, especially as a female. You won't get bulky with those 5kg weights, believe me, as someone who has spent 2 years working very hard to put muscle on, you need to eat at least at maintenance and lift some progressively heavy weight to put on muscle