My sister lost almost 80 lbs using Medifast. I think she wanted a change and so recently she stopped using medifast and tried carb cycling which I had been doing. She does not really have the self control needed for carb cycling or really any food plan that just requires cutting down what you eat and so she is starting to gain weight. She has recently decided to go back to Medifast because it is what works for her.
Similarly, I have lost approximately 25-30 lbs since December when I started my first 6 month Diet Bet game. I did so using a of carb cycling as taught by Chris Powell. Even that was modfied to fit what I could do though. It calls for 5 servings of protein a day and beans do not count as protein in his plan, they count as carbs. Well, i live in West Africa (although I am American) and do not have access to grocery stores, only local outdoor markets. I have meat but I do not have enough for 5 servings a day, nor do I really have money to buy enough to have 5 servings a day on a prolonged basis. So, I do not worry so much about the protein. What I do really focus on is only having one servings of carbs on my low days. Either way, I found what works for me.
Well, I did it for 6 months or so and felt like I needed a change so I dropped the carb cycling and have just been counting calories. Let me tell you, although counting calories is effective, I have not been anywhere near as consistent counting calories as I was when I was doing carb cycling so guess what? I'm going back to carb cycling.
The point is, we each have to find what works for us and once we find what works we need to stick with it. It's like the saying goes, "if it ain't broke, don't fix it".