Hey Maurene!
I have some friends who were actually WW trainers for a long time. And then, after they stopped doing that, they gained weight. Recently they tried to get back onto WW, but just couldn't manage to follow through. They decided to try Medifast, and have been quite successful.
But that said--I'm wondering why you would want to start with Medifast and then switch. Medifast does have transition and maintenance plans, once you lose the weight you need to lose. And changing over to WW--well, I think you could expect your weight to bounce a little. They are really different programs.
Are you sure that you can't make WW work for you? Because here's the thing with Medifast: You get one meal of "real food" a day--the rest is their packaged food, and each Medifast "meal" is around 100 calories. Getting started is the hard part--you can expect to feel hungry and even light headed until your body's metabolism adjusts. If I had a full-time job outside of home, I'd take a long weekend to start Medifast, just so I wouldn't feel so bad at work.
On the other hand, Medifast
does work! If you stick with it. You might want to do some reading on their website to make sure you know what you're getting into. And, I'd say order a 2-week package to start with, in case you find it's not for you.
Also, many people don't know that they can customize their first order--you don't have to take the "starter pack" exactly as is. So if you suspect there are meals you won't like, you can substitute for those you think you will like.
I wish you a lot of luck with your weight loss! I hope these ideas help you decide what to do.
Jay