You've been told for years (well, months, anyway) that chocolate is good for the heart . And, it tastes good, too. The trouble is that nothing is good for you if you take too much. Now Australian doctors have made the unfortunate discovery that older women who eat chocolate every day have weaker, thinner bones than those who scorn the delicacy. Their study is published in the American Journal of Clinical Nutrition.

Over 1,000 women aged 70 to 85 who were taking part in a clinical study of calcium intake and fracture risk provided information. They were asked how often they ate chocolate: less than once a week, 1 to 6 times weekly, and once or more times a day. Bone density and bone strength were measured using dual-energy X-ray absorptiometry (DXR), computed tomography (CT), and ultrasound.

Women who ate chocolate daily (group 3) had a 3.1% lower bone density, on average, than those eating it less than once a week. And their heel and tibia bones were weaker.

It's clear the chocolate was the villain. Women eating chocolate weighed less, had a lower body mass index ( BMI ), consumed more calories, and had a higher socioeconomic status. But they ate the same amount of fresh fruit and vegetables, saturated fats, and carbs (although they ate less protein, fiber, and potassium).

The doctors say this effect (the lower bone density) may be due to a constituent of chocolate rather than a different lifestyle or diet in chocolate lovers. "More studies are needed". In the meantime, I'll rely on the fact that only women were studied, and continue with my daily small square of dark choc.