I guess it IS true - but it is not a prescription for recklessness!
The people in the study all lived in California. Almost 70% were men. The average age was 57. The people in the study were not in an experiment but answered survey questions about their health and history. The 975 who responded exercised more than 3x a week on average and ate chocolate 2x a week.
The people who ate the chocolate had lower BMIs than those that did not. The scientists said that this was not related to overall caloric intake or exercise variation. As this was not an experiment, people were not followed over time and there was no confirmatory evidence (no proof that the responses to the surveys were accurate (i.e.height and weight, exercise, food frequency - were all self report and we tend to misrepresent ourselves).
Chocolate does have antioxidants and health promoting properties. It is certainly possible to include chocolate in the diet without having the saturated fat and excess calories do you harm.
I read yesterday, in a story about this research, that one should eat very small amounts, about an ounce a day (or less) and that cocoa powder was a great alternative.
I have a friend who has a little Hershey miniature once a day or so and I bake cake and cookies with the cocoa. I exercise daily and my chocolate is part of my overall calories.
Here is the summary of the research letter published in the Archives of Internal Medicine.