(Adds company background, updates share move)
May 18 (Reuters) - Campbell Soup Co Chief Executive Officer Denise Morrison will step down, the company said on Friday, while also cutting its full-year earnings forecast due to costs related to its acquisition of snacks maker Snyder's-Lance.
The company's shares fell nearly 4 percent to $37.8 in premarket trading and were set to open at their lowest in five years.
Morrison will step down immediately and be replaced by board member Keith McLoughlin in the interim, Campbell said, but provided no reason for her departure.
Morrison became CEO in August 2011 after more than eight years at Campbell, but has in recent years struggled to turn around the company's mainstay soups business.
She has focused on diversifying away from soups into snacks and acquired Snyder's-Lance for $4.87 billion.
Campbell reported third-quarter sales in line with analysts' estimates, as higher sales in its snacks business offset declines in its Americas Simple Meals and Beverages unit.
Organic sales in the Americas Simple Meals and Beverages business, which includes soups, fell 2 percent in the quarter due to weak demand for condensed soups, V8 juices and Plum products.
Gross margins fell to 29.1 percent from 35.9 percent, below the company's expectations, mainly due to higher commodity and freight costs.
Campbell now expects full-year earnings per share to fall between 5 percent and 6 percent, compared with its earlier forecast of a 1 percent to 3 percent decline. The prior outlook did not include the impact from the acquisition of Snyder's-Lance.
Net loss attributable to the company was $393 million, or $1.31 per share, in the quarter ended April 29, compared with a profit of $176 million, or 58 cents per share, a year earlier.
The loss reflected a $647 million charge related to its Campbell Fresh division.
Net sales rose to $2.13 billion from $1.85 billion. (Reporting by Nivedita Balu in Bengaluru; Editing by Sai Sachin Ravikumar and Maju Samuel)