Thanks for telling your experience with those diets. I know someone who did Slimfast at home (just one small meal, the rest of the day Slimfast shakes) and she walked on a treadmill everyday. She did lose all the weight she wanted to lose - which was a substantial amount - and then she put it all back on! AND she had a friend coaching her and supporting her every step of the way.
Sometimes, just having someone else make the food decisions for you (including the preparation of the food) makes all the difference.