Medifast is a company that helps people lose weight by selling them delicious, healthy food.  They've shown fantastic growth over the last few years, even in a rough economy.  Why?  Well clearly, obesity is nothing short of an epidemic.  Everyone you know is trying to lose weight.

108% growth rate through fiscal 2009, and here is another nugget: they have beaten analyst estimates six quarters in a row.  Analysts, shmanalysts.  There's only 3 that cover the company.  This definitely qualifies as under the radar.

Why did Forbes recently call Medifast the #1 small company in America?

"We dropped companies with fuzzy accounting or looming legal troubles. We also compared the stock performance of each company with that of its peers. Shares of last year's list members outpaced the Russell by 10 percentage points," Forbes says, "Medifast is on a tear. Sales have marched north 41% a year over the past five years and earnings per share have increased 35% a year during the same period. The past 12 months have been even better, with sales increasing 69% and earnings jumping 120%."

Let's look at a somewhat cynical endorsement of the stock from competing stock picking site fool.com:

http://www.fool.com/investing/general/2010/06/02/why-medifast-will-go-the-d...

"the key to becoming a successful diet company isn't ensuring that people succeed with your product. It's all about marketing and becoming a recognized global brand."

I don't actually agree with this analysis, I think the growth in Medifast is related to its customers' success.

Here is a study in the Nutrition Journal which compared results of study participants on the Medifast meal replacement program and an isocaloric, food-based diet:

"Weight loss at 16 weeks was significantly better in the Medifast group (MD) versus the food-based group (FB) (12.3% vs. 6.9%), and while significantly more weight was regained during weight maintenance on MD versus FB, overall greater weight loss was achieved on MD versus FB. Significantly more of the MD participants lost ≥ 5% of their initial weight at week 16 (93% vs. 55%) and week 40 (62% vs. 30%). "

http://www.nutritionj.com/content/9/1/11

That's about it.  It's a fast growing company that is both helping its clients lose weight and profiting from a growing trend in this country (obesity and people's desire to rescue themselves from it).