Risk and reward
The mayor embraces risk and, though he doesn't particularly revel in failure, he is not afraid of it, said Gibbs.
She recalled his telling a story of having spent a day skiing. Afterward, a skier remarked proudly that he had not fallen once. Bloomberg was unimpressed. "He said, 'That means you didn't try hard enough,'" Gibbs said. "If you succeeded at everything, you left opportunities on the table."
Bloomberg himself has left few opportunities on the table. After graduating from Johns Hopkins University with a degree in engineering, he got an MBA from Harvard Business School and then, in 1966 at the age of 24, he moved to New York for a job with Salomon Brothers, an investment bank.
He rose quickly, eventually overseeing the firm's information systems.
In 1981, squeezed out of the bank in a merger, he started Bloomberg LP, the financial news and information company used by Wall Street's trading firms. It has made him rich.
Since then, he has donated more than $2.4 billion to a variety of causes and organizations. About half of that -- more than $1.1 billion -- has gone to Hopkins, which named its school of public health after him.
"He's driven by the metric of how do we make the most impact in terms of improving health and saving lives," said Dr. Michael J. Klag, dean of the Bloomberg School of Public Health. "Mike is a data-driven guy, he's a numbers guy."
Klag credits the businessman's investments in public health with paying big dividends.
"New York is now the healthiest city in America because of what he's done," Klag said.
It's also one of the safest, with the lowest murder rate of any big city in America. And traffic deaths and fire deaths are the lowest since the city started keeping records in 1916.
"Parents from around the country used to dissuade their kids from moving to New York because it was dangerous," Bloomberg said last week. "That doesn't happen any more. Parents want their kids to move here because they're probably safer than where they're coming from."
Putting a dent in obesity
Bloomberg's focus on food is recent and the data to support it are not as strong.
"With tobacco, we have a pretty established set of policies we know are effective, but with obesity, it's still new," New York City Health Commissioner Dr. Thomas A. Farley told an audience at Fordham University in New York during a conference last fall on Bloomberg's public health legacy.
But talking about legacy is "a little presumptuous," according to Peter Zimroth, a lawyer with Arnold & Porter, which has represented the restaurant industry.
"The legacy is yet to be written on some of these initiatives," he told the conference, adding that the evidence that such efforts would reduce obesity was itself thin and could wind up being counterproductive. "There's a limited amount of capital, I think, that government has to engage in coercive measures," he said.
Bloomberg sees restrictions on food as a critical component to his public health mission, according to Klag. "He sees this avalanche of diabetes coming," he said. "That's why he attacks the sugar intake."
In reaching for opportunities, Bloomberg has lost his footing several times. In addition to losing his effort to ban large, sugary drinks, he failed in his bids to get a soda tax adopted and to ban the use of food stamps to buy soda.
The so-called soda ban provoked ridicule from some observers. "I think this is what makes liberals look like elitist bullies who think they know everything and can tell people what to do," Bill Maher said on his HBO show "Real Time." "You shouldn't have to clear what you eat with the municipal government."