INS and diabetes mellitus: However, not all studies demonstrate the benefits of dark chocolate on glucoregulatory outcomes, as dark chocolate containing 450 mg of polyphenols did not improve insulin and glucose responses in hypertensive participants with diabetes when administered 60 min prior to a 75 g oral glucose load.6 Rostami et al17 also found that daily consumption of 25 g of dark chocolate for 8 weeks did not improve fasting glucose, insulin, and HbA1c levels in hypertensive participants with diabetes.