Hi,
I once tried to eat nothing but special K and it didn't work. However, I couldn't sustain it, mainly beause I love food too much and got bored! Plus its not healthy. I still eat special K but I have a small bowl and some fruit now for breakfast, a good sized bowl of soup for lunch and a proper dinner. The best thing I ever did was make myself aware of calorie intake. I went shopping and wrote down everything I bought - no diet stuff, just food I like - and actually thought about what was in my food.
In two weeks I have already lost 5 pounds and 2 inches on my waist, just through being sensible, going for a walk each evening, and just being aware of what I am cooking It has made a huge difference. I haven't changed the way I eat too much, just portion size really. It is the healthiest way I have ever lost weight and I feel great - just try it! I have whats called 'Nat's Fat Book' which helps me record on a daily basis.
Also, this site is quite useful - it can calculate anything ou eat, including take outs and any recipes you input. Have a look.
Lots of luck with you, I look forward to reading about how its going.
Nx