Does anyone use food supplements?

I have found a bunch of websites that make food for bariatrics or for weight loss in general, high  protein, low carb, low calories, etc and if you follow their meal plan you are supposed to get back on track.

Medifast is out there
Smart for Me
Focus 28
 

There are tons more but I just wonder if anyone on the boards has ever used those to either lose weight or maintain?  I have done Medifast before and lost 30 lbs but it is tough.  Similiar to Optifast.