Nelson Mandela is still alive because . . .

Perhaps because he was in good shape, and then, just when his fighter's muscles would have begun to turn to fat, were he to have led his country as a free man, he was forced to live for 27 years as an adult with a low-protein, low-calorie diet, and daily physical labor. Notwithstanding the evil of it, Madiba's resulting TB, etc.  One cannot imagine President Zuma living into his 90s.