I am a bit puzzled by this Slimming World diet.
I really liked the Rosemary Conley diet class because the teacher was the first person I'd heard state the obvious: if you eat more calories than you use you will gain weight. Also the class stressed the importance of and incorporated an hour of exercise, but, as I said, there aren't any classes in this area any more.
From what I've seen so far of the Slimming World diet you can eat limitless quantities of some things, which while they may not be high in fat or sugar, have calories - so you can end up eating lots of calories.
And they make no mention I can see of exercising or at least moving. So it's learning a whole new way of thinking.
But several people have told me of their great success with it so perhaps they do know what they're doing - they call it food optimisation. However I mustn't fall into the trap of eating grapes by the bunch again. Last time I did this sort of diet I stuffed myself on grapes in spite of Husband telling me they're full of sugar and you shouldn't do that. I did lose weight though ...