If that craving for chocolate sometimes feels like it is coming from deep in your gut, that’s because maybe it is.

A small study links the type of bacteria living in people’s digestive system to a desire for chocolate. Everyone has a vast community of microbes in their guts. But people who crave daily chocolate show signs of having different colonies of bacteria than people who are immune to chocolate’s allure.

That may be the case for other foods, too. The idea could eventually lead to treating some types of obesity by changing the composition of the trillions of bacteria occupying the intestines and stomach, said Sunil Kochhar, co-author of a new study.

Kochhar is in charge of metabolism research at the Nestlé Research Center in Lausanne, Switzerland. The food conglomerate Nestlé SA paid for the study. But this isn’t part of an effort to convert a few to the dark side (or even milk) side of cocoa, Kochhar said.

Kochhar compared the blood and urine of those 11 men, who he jokingly called “weird” for their indifference to chocolate, to 11 similar men who ate chocolate daily. They were all healthy, not obese, and were fed the same food for five days.

The researchers examined the byproducts of metabolism in their blood and urine and found that a dozen substances were significantly different between the two groups. For example, the amino acid glycine was higher in chocolate lovers, while taurine (an active ingredient in energy drinks) was higher in people who didn’t eat chocolate. Also chocolate lovers had lower levels of the bad cholesterol, LDL.

Still to be determined is if the bacteria cause the craving, or if early in life people’s diets changed the bacteria, which then reinforced food choices…What matters to Kochhar is where the research could lead.

Kochhar said the relationship between food, people and what grows in their gut is important for the future: “If we understand the relationship, then we can find ways to nudge it in the right direction.”

—Seth Borenstein, Associated Press, 10/12/07