Hi there! I lurk on H&F on TN but do not post a lot.
I have been wanting to lose about thirty pounds and do not know the best way to work on it. I have been researching Medifast and Nutrisystem, but will you gain back weight after you finished those? Is it better to go with a lower calorie and workout plan?
Generally, a plan that works with your real life (i.e. eating food) will work better long term than one that replaces meals with shakes. It is possible to transition and not regain weight, but it requires changing your eating habits - so most people will do better just doing that off the top.
Start tracking calories on Sparkpeople, Livestrong, or join Weight Watchers. Make a few changes at a time in your diet, and be conscious of what you're eating. That's how you make changes that result in lasting weight loss.