Warren Buffett: Brilliant Investor, Lousy Nutritionist

Liquid candy.

Photographer: Daniel Acker/Bloomberg

At his annual meeting last weekend, Warren Buffett defended his daily intake of Cherry Coke (700 calories) with the sort of folksy logic that has made him so appealing. "I like fudge a lot, too, and peanut brittle," he explained. "I am a very happy guy. If you were happy every day -- and it may be hard to measure -- you are going to live longer as well, so that may be a compensating factor."

Buffett is of course correct that there is no reliable metric for happiness (though that hasn't stopped people from trying, on a personal and national scale). There are, by contrast, many ways to measure the effect of soda on human health. To summarize: It is bad.

While soda drinking might be good for Buffett's portfolio, it's unquestionably harmful for public health. Many studies show that drinking sugar-sweetened beverages every day leads children and adults alike to gain weight, mostly because few soda drinkers compensate by cutting other calories. This could help explain why obesity rates worldwide have risen along with increased consumption of sugar-sweetened beverages.

Researchers have also found strong links between soda-drinking and diabetes, heart disease and gout. And because sodas contain high levels of phosphoric acid but no calcium, they can also have an ill effect on children's bone development.

As for Buffett's suggestion that soda-drinking is a matter of personal choice, he may be immune from the $1 billion a year that soda makers spend on advertising, much of it directed at children, and by the drinks' low prices and ready availability. When taxes are levied to raise the price of the drinks, consumption falls, according to a study of Mexico's soda tax (a study partly funded by Bloomberg Philanthropies). Emerging evidence suggests this has the potential to reduce obesity.

Buffett is certainly free to indulge his sweet tooth, and he seems to have a (healthy?) respect for the need for moderation. He can also be expected to defend his company's 9 percent stake in Coca-Cola. But generalizing from personal experience is not the best way to formulate public policy. In fact, it tends to work better the other way -- using aggregate data to guide personal behavior. On that score, here's some nutritional advice for Mr. Buffett: Please remember to stay hydrated.

To contact the senior editor responsible for Bloomberg View’s editorials: David Shipley at davidshipley@bloomberg.net.