In July 2017 researchers from China published their review of the scientific literature to assess the effect of chocolate and risk of coronary heart disease, stroke and diabetes. A total of 14 studies involving 508,705 individuals were included in the review. One serving of chocolate was defined as 30 g. Results showed that chocolate consumption appeared to reduce the risk of all three conditions. For both coronary heart disease and stroke, there was little additional risk reduction when consuming chocolate more than 3 servings/week and for diabetes, the peak protective effect of chocolate appeared to be 2 servings/week. No benefit was observed when increasing consumption above 6 servings/week.
Yuan S et al. Chocolate Consumption and Risk of Coronary Heart Disease, Stroke, and Diabetes: A Meta-Analysis of Prospective Studies. Nutrients. 2017 Jul 2;9(7)