Does your diet include unhealthy sources of protein, perhaps burgers, hot dogs and fried chicken in excess? Do your heart a favor and choose your proteins wisely. Legumes are a great source of heart-healthy protein. They include beans, peas and lentils. Legumes are typically low in fat and contain no cholesterol. They're also rich in folate, potassium, iron and magnesium. Legumes also contain beneficial fats and soluble and insoluble fiber.