Chocolate can keep you regular. At least, it can keep your heartbeat regular, according to researchers at Harvard T.H. Chan School of Public Health and in Denmark. A Chan school news release reports that the study, which included 55,502 men and women participating in the Danish Diet, Cancer, and Heath Study, looked at body mass index, blood pressure, and cholesterol, diet and lifestyle at the time participants were recruited, between December 1993 and May 1997. When the researchers looked at the incidence of atrial fibrillation (AF)—a common and sometimes dangerous type of irregular heartbeat, over a 13-year followup period, they found that, compared with those who ate a one-ounce serving of chocolate less than once per month, men and women who ate one to three servings per month had a 10 percent lower rate of AF; those who ate one serving per week had a 17 percent lower rate; and those who ate two to six servings per week had a 20 percent lower rate. The benefit leveled off slightly with greater amounts of chocolate consumption, with those eating one or more servings per day having a 16 percent lower AF rate. And yes, the results were similar for men and women.