Remember, there is nothing intrinsically magic about slimming world, it is all about calories like everything else. The rules exist that stop you over consuming on things that have high calories but dont fill you up, and to replace those with things that are low in calories or fill you up.
If you eat three pounds of rice a day, no amount of food optimising is going to undo the calories consumed. SW is a low calorie diet in which you dont need to think about the calories.
I use food focus every now and then to audit what i have eaten. It is really easy on SW to eat far too little in terms of calories that your body needs. For a 5ft11 gent such as myself, who is now moderately active, to not gain or lose weight i should be consuming 3,300 calories a day.
To lose two pounds a week, i need to cut a thousand out of that. The problem is, that I find, without a concerted effort it is quite hard to eat anything like 2,300 calories a day on SW. My average is somewhere between 1200 and 1800, more usually 1400.
If you read up on online fitness and weight loss sites, they all have a very clear message. You should *not* eat less than your BMR (2100 for me), it doesnt help weight loss, it slows down your metabolism, burns muscles and makes a gain more likely as soon as you leave the plan.
On the other hand, my GP says 1200 is fine as long as you are getting the right nutrition and you have a fair bit to lose.