I agree with previous comments made: if one takes in less than they expend they will lose weight regardless of whether or not those calories are in candy, cereal, steak, etc. However, one must also maintain a balanced diet in order to get all the necessary vitamins and nutrients essential for remaining healthy. Losing weight shouldn't be the only issue, especially if it is placing someone's health at risk. Eating two bowls of cereal in place of two meals limits one to only one meal/day which could contain any fruits or vegies. I'm not a registered dietician or anything but this sounds unhealthy to me. Jenny Craig, NutriSystem, Weight-Watchers...these are all much more balanced approaches to weight loss. (Alli is a diet pill and not a diet. One must follow a low-fat diet along with it as well as limiting one's calories).
But drinking Special K as a protein supplement could be wise for those who ARE going on silly low-cal. diets, as it is a means of adding essential protein, whic might have been otherwise missed.

One really must read the label however--there are those who are allergic to whey proteins and milk and could be at great risk by drinking this product. I only learned of these ingredients because i questioned how flavored water could contain protein. If i am to believe what is on the internet, there has already been one death of a 10 year-old child from either this drink or one similar to it...because flavored water seemed harmless enough and so the label wasn't carefully read.