LOS ANGELES (Reuters) - Fast-food chain operator Burger King Holdings Inc posted quarterly results that topped analysts' view, helped by its $1 double cheeseburger offer, more restaurants, lower taxes and deflated food costs.

The second-largest hamburger chain yesterday said profit and revenue came in better than Wall Street had expected, helping allay investor concerns over high US unemployment levels and friction between the company and its franchisees.

Shares in Burger King rose 2.7 percent.

The home of the Whopper reported net income of $50.2 million, or 37 cents a share, for the second quarter ended on December 31. That was up from $44.3 million, or 33 cents a share, a year earlier.

Results from the most recent quarter topped analysts' expectation for a profit of 34 cents per share, according to Thomson Reuters.

Revenue rose to $645.4 million, above analysts' estimates for $634.8 million, helped by an increase in the number of Burger King restaurants. Worldwide restaurant margin also improved a better-than-expected 20 basis points to 13.8 percent.

Bernstein analyst Sara Senatore said a lower tax rate helped drive the profit beat. Lower costs for food and paper also helped margins.

After weathering the US economic downturn better than most other restaurant categories, the fast-food segment has since seen traffic weaken. High unemployment has resulted in fewer people dining out and operators have responded by discounting aggressively, putting profits in danger.

Analysts continue to monitor friction between Burger King and its franchisees, who have complained that discounts and promotions used to lure more traffic are making it harder for them to turn profits.

Burger King's worldwide same-store sales fell two percent in the quarter, driven by a 3.3 percent decline in the United States and Canada, as rampant discounting and continued high unemployment weighed.

"These results confirm later thoughts that December likely saw a significant deterioration that probably continued into January," J.P. Morgan analyst John Ivankoe said in a client note.

While Burger King's latest quarterly same-store sales for the US were weaker than the Street expected, they were still stronger than the eight percent decline posted on Wednesday by Yum Brands Inc, parent of Taco Bell, KFC and Pizza Hut. Wednesday, Yum reported a profit that topped analysts' targets due to new restaurant openings.

Meanwhile, bigger rival McDonald's Corp has been gaining share. The world's biggest hamburger chain said its closely watched US same-store sales gained one percent in December after two months of declines.