US scientists have discovered residues of cocoa - from which chocolate is made - in pots dating to 600 BC. This pushes back the earliest chemical evidence of chocolate use by about 1,000 years.

Earlier, in the dark... Last month, dark-chocolate chemistry made news, thanks to a study by the Nestlé Research Center. Scientists there found a way to make that company's dark candy a tad more healthful, without affecting its taste.

They replaced table sugar equal to 2.5 percent of the candy's weight with an identical amount of calcium carbonate, the stuff of chalk. Then, every day for 2 weeks, they gave two 50-gram snacks of either the modified or the unmodified chocolate to 10 male volunteers. After waiting another 2 weeks, they repeated the experiment, this time giving each man the other chocolate.

During the weeks they ate the calcium-fortified confection, the men excreted roughly twice as much fat as in weeks when they downed regular dark chocolate, note Yasaman Shahkhalili and her colleagues in the February American Journal of Clinical Nutrition. Virtually all of the extra fat was of saturated types characteristic of cocoa butter. Because of the fats' excretion and the slight reduction in the candy's sugar, the modified candy provided 9 percent fewer calories than the unaltered chocolate
did.