Paul Polman, CEO of margarine maker Unilever, has criticized butter in the past, saying the dairy fat "kills." With sales of the company's spreads sagging, he is now embracing it.

In what Unilever Foods President Antoine de Saint-Affrique calls a "fundamental turnaround" of a $4.8 billion business that has struggled for years, Unilever in September added butter to Rama in Germany, the biggest spread brand in that market. After years of positioning butter as the enemy of margarine, the battle is over, he said in a Dec. 5 investor conference.

Unilever's surrender comes as butter makes a comeback, lifted by new nutrition research, cooking shows like "The Great British Bake Off," and a consumer embrace of all things natural. Per-capita butter consumption hit a 44-year high in 2012, according to U.S. government data, while margarine is at a 70-year low. In Germany, butter outsells margarine by a 3-to-1 margin, and the gap is widening as the latter failed to grow in 2013, according to data tracker IRI.