With surveys like Zagat’s and Consumer Reports’ putting Five Guys among the best-tasting burgers available, it’s perhaps not surprising that the chain is the fastest-growing hamburger shack in the country. In fact, a new report says that new Five Guys eateries outnumbered new McDonald’s by greater than 4:1 in 2010.

The folks at QSR Magazine have released their list of the top 50 quick-service chains in the country and while Five Guys only had a total of 736 restaurants last year, 195 of those were new. Compare that to McDonald’s which only opened 47 new outlets in 2010.

Of course, McDonald’s already has more than 14,000 restaurants in the U.S., so it’s not quite worried about upstart Five Guys just yet.

But just because a restaurant chain is huge doesn’t mean it stops expanding. Subway, which has a ridiculous 23,850 stores, added the most outlets last year — 816, or 17x the number of new McDonald’s!

For Quiznos fans, that sandwich shop chain lost a whopping 600 stores in 2010, by far the worst-hit of the restaurants on the list. The closest was KFC, which shuttered 107 eateries last year.

Top 50 Unit Breakdown Sorted by Change in Units [QSR Magazine]

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