Fast-food chain Burger King ( BKC) posted better-than-expected earnings on Wednesday, but executives said they are cautious going forward. Despite the company cutting its full-year outlook, its shares jumped 6% to $17.98 in morning trading. Earnings for the company's third fiscal quarter grew 15% to $47 million, or 34 cents a share, from $41 million, or 30 cents, in the year-ago period. Analysts expected earnings of 33 cents. Revenue inched up 1% to $600 million. Burger King said cost-cutting initiatives and tax savings helped offset a decline in store traffic in March, especially in Germany and Mexico. Worldwide sales of stores opened at least a year rose 1%. In North America, same-store sales rose 1.6%. The company forecast full-year earnings in the range of $1.39 a share to $1.42 a share, down from its prior outlook of $1.44 a share to $1.49 a share, on worries of continued economic instability and the unknown effects of the swine flu outbreak. Other fast-food companies, such as McDonald's ( MCD), have profited from the recession, as consumers trade down from higher-priced options. Burger King has seen sales rise, but its gains at established locations have trailed those of McDonald's -- a pattern that repeated itself in the third quarter.