The Austin, Texas-based company caters to health-conscious and generally upscale shoppers, a niche that has helped it outperform mainstream rivals such as Kroger Co, Safeway Inc and Supervalu Inc -- which are fighting for every sale.

Net income at Whole Foods jumped 31 percent to $117.7 million, or 64 cents per share, for the fiscal second quarter ended April 8. Analysts, on average, had expected a profit of 59 cents per share in the latest quarter, according to Thomson Reuters I/B/E/S.

Same-store sales at Whole Foods, the biggest U.S. grocery chain that focuses on organic and natural food products, rose 9.5 percent -- more than the 8.8 percent gain analysts had expected on average, according to Thomson Reuters data.

Total sales were up almost 14 percent at $2.67 billion.

Based on results from the second quarter, Whole Foods raised its full-year profit forecast to a range of $2.44 to $2.47 per share, from $2.28 to $2.32 per share previously.

Shares of Whole Foods, which are up more than 40 percent so far this year, rose 3.2 percent to $87 in extended trading.