This seismic shift in the U.S. food industry is creating hurdles for food behemoths such as General Mills, Kellogg Company ( K - Free Report ), Mondelez International, Inc. ( MDLZ - Free Report ), The Kraft Heinz Company ( KHC - Free Report ), and others, thus making it harder for legacy brands to improve sales. In the recently reported quarter, General Mills' adjusted earnings and revenues declined 9% and 3.5%, respectively, year over year due to weak sales across the board, barring Convenience Stores & Foodservice, and Europe & Australia segments. Its core U.S. Retail business' sales declined 5% primarily due to double-digit declines in the domestic yogurt operating unit and a 7% decline in cereals.