Replacing some carbohydrate intake with protein may actually reduce the risk of ischemic heart disease. The research teams, from the Harvard School of Public Health, were surprised as they reasoned from ecological studies that animal protein is associated with an increased risk of heart disease. Those studies compared the diets of people in different countries and found that the lowest rates of heart disease were in areas where the least amount of red meat was consumed. After controlling for age, the investigators determined that a higher intake of total protein was associated with a lower risk of ischemic heart disease.

the lowest rates of heart disease were in areas where the least amount of red meat was consumed

Now we have research from the Halls of Harvard showing that more protein will actually reduce, NOT increase, heart disease as is commonly purported. The authors also do not address the more obvious reasons why increased protein lowers heart disease. Protein is usually associated with fat, so if one consumes more protein, one must reduce their carbohydrate intake.

American Journal of Clinical Nutrition August 1999;70:221-227.