AGE: 58 OCCUPATION: Chairman and CEO, Kraft

Last year Fortune named this mac-and-cheese lover the single most powerful woman in American business. But Rosenfeld’s August decision to split Kraft into two companies—a $32 billion global snacks maker that she’ll helm and a slower-growing $16 billion North American grocery unit that she won’t—has diminished her role. Whether her strategy (which included announcing 1,600 layoffs in January) succeeds in satisfying growth-obsessed Wall Street remains to be seen.

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Photograph: William Deshazer/Chicago Tribune