Whole Foods Market Inc., the largest U.S. natural-foods grocer, said profit fell 13 percent in the second quarter on expenses related to its acquisition of Wild Oats Markets Inc.

Net income dropped to $40 million, or 29 cents a share, in the three months ended April 13, from $46 million, or 32 cents, a year earlier, Whole Foods said Tuesday in a statement. Sales rose 28 percent to $1.87 billion, missing the $1.89 billion average estimate of 12 analysts surveyed by Bloomberg.

The Austin, Texas-based retailer acquired Wild Oats in August for $565 million to compete against Safeway Inc. and Trader Joe's Co., as consumers, hurt by higher gas and food prices and the worst U.S. housing market in a quarter century, rein in spending.

Sales at stores open at least a year rose 6.7 percent in the quarter.

The retailer reiterated its forecast for full-year same- store sales growth of as much as 9.5 percent, and total revenue growth of as much as 30 percent. It expects sales, excluding Wild Oats, to rise about 20 percent.