Slimfast is okay if you are not trying to lose weight. It is loaded with vitamins, minerals, and protein, but has way too many carbs. If I were you, I would increase my fiber to 25mg per day, and you should see a few pounds drop like that. Fiber makes you feel full longer, in addition to a plethora of other health benefits. Make sure you are eating at least three meals a day, and several snacks. Your metabolism won't work right, if you don't give it anything to burn. Also exercise portion control, which you may be doing now, but it doesn't work if you are eating more than the per serving size. Make your meals balanced, that is another key. Don't cut out too many carbs and go all protein, dieting extremes rarely ever work for the long term.
I am not sure if you have ever tried it, or if you can even get it where you live, but I highly recommend Kashi cereal. It makes for a good breakfast and lunch, as long as you are using skim milk. It is full of fiber, and all kinds of other good stuff, plus I find the taste to be incredible for being a healthier choice. I also love tuna fish (in the pouch or in water) mixed in with lowfat cottage cheese for lunch. It is quick and easy, and leaves you feeling full for hours. Not everyone loves tuna though, so invent your own low calorie, low fat, low carb, high protein lunch. I also love pineapple, vanilla yogurt, and a banana blended with ice for a nice sweet treat. It is yummy and makes you feel like you are not being deprived.
Bottom line is, read your labels. Increase your protein and fiber, and lower your carbs and sugars. No more than 30% of your calories should come from fat, and make sure you are eating when you are hungry. If you don't eat when you are hungry, that will turn into binge eating eventually. Never skip breakfast, as I believe it helps set your metabolism for the entire day. When you are walking, invest in a step counter so you can see the amount of calories you are burning. Try walking the same amount at a faster pace, get your whole body into it. Even ankle weights and wrist weights will help burn more calories, as they offer a little resistance. You can even wear them around the house while you are doing chores and such. I hope this may help some! Good Luck!
Here is the nutrition information for SlimFast, plus you can find other nutritional facts too.
Calories in Slim-Fast Foods Company - Slim-Fast