Not every one knows this, but in addition to the six meals that you eat on Medifast, you are allowed to have two snacks each day. Granted, these snacks can't be anything that you want. There is a snack list from which you have to choose. But, they do offer you some decent choices. And one of the choices on the list are popsicles. I believe that this option receives a lot of interest because they are a sweet or dessert like option which many people crave when they are dieting. But you should now that you probably shouldn't just blindly choose the first Popsicle you pass in the grocery store because they are not all the same.
Ideally, you want for them to be fruit flavored, but you most definitely want them to be sugar free. One of the main principles behind this diet is not taking in too many carbohydrates so that your body is able to burn fat rather than carbohydrates to get into a metabolic state called ketosis. And if you have a snack that is full of sugar, then this process might be delayed or even thwarted. Also, this is just my opinion, but I try very hard to stay away from artificial sugars. I prefer products with sugar alcohols. They are converted to glucose more slowly and don't require insulin for this process, which means that your blood sugar is kept stable.
Here's another idea and please take this only as a tip. This is just something that I do which I've found helpful. But if you have any specific questions about compliance, please ask the company itself. I freeze some of the Medifast shakes to make my own popsicle that is extremely low in sugar. I like to use the dutch chocolate flavor with a little bit of water. You can either freeze it in a mold, an ice cream tray, or in a cup (to later be eaten by a spoon.) I find that this home-made options tastes sort of like a fudge pop to me. And because I know exactly what is in it, I don't have to worry that I'm consuming something that I shouldn't or something that is going to spike my blood sugar.
It's not that it's really hard to find a sugar free product in the grocery store (that hopefully includes sugar alcohols,) but sometimes I like variety and having a chocolate option is nice also. However, you could also try the vanilla or banana flavoring depending on your preferences.
If you'd like more information about what life is really like on Medifast, feel free to check out the free eBook "Getting The Most Out Of Medifast" at http://easiest-diet.com/free-medifast-ebook/html