I’m not a Coke drinker; I shy away from soda generally and may be one of the few people who actually prefer Coke Zero. But one of my closest friends loves the stuff, and I’m all for truth in labeling anyway.
That’s why I asked Coca-Cola on Twitter where they got the numbers they include prominently on their Fridge Pack:

The only calories in Coke come from sugar, and the FDA requires that nutrition labels use an estimate of 4 calories per gram of carbohydrates (of which sugar is one). At 140 calories per can, we should expect to find 35 grams of sugar in that same serving size. (140 / 4 = 35.) But look at the nutrition label:

Each can, according to the label, has 39 grams of sugar, not 34. This should result in an estimate of 156 calories per serving (39 * 4), not 140. I can’t reconcile these numbers, no matter how much research I do. And of course, Coca-Cola hasn’t responded to my tweet.
It sounds like a small difference, but ask your favorite dieter whether those 16 calories would make him or her a little less likely to have that second Coke this afternoon. Given the Fridge Pack’s popularity (PDF), even a small portion of customers passing on a can every day or two could hold back Coke’s revenue stream by some percentage investors find noteworthy. (It’s worth saying that investors—and especially market analysts—find very small percentages noteworthy.)
I have to think that a company with so massive a legal department wouldn’t let this kind of thing happen by accident, so I believe there’s some explanation for the strange math in play here. I just want to know what it is.