Changing consumer tastes and habits have rocked the processed food sector, letting upstarts steal market share from traditional brands with the growth of e-commerce, social media and interest in sustainability and health. Natural, organic, artisanal or plant-based products have been a bright spot in an otherwise tepid market, where the need to buy growth and cut costs led to Danone's ( DANO.PA ) purchase of WhiteWave and failed attempts by Kraft Heinz ( KHC.O ) to buy Unilever and Mondelez ( MDLZ.O ) to buy Hershey ( HSY.N ). Nestle, the world's largest processed food company which has recently become a target of activist shareholder Third Point, said on Thursday it has agreed to buy Sweet Earth, a U.S. maker of frozen meals, burritos and burgers that use meat substitutes.