Whey Protein contains fats that have been proven to contribute to heart attacks and strokes. Look at the whey labels and you will see they contain relatively large amounts of saturated fat and cholesterol. If you are taking lots of whey protein supplementation, you are eating lots of butterfat. Soy doesn't have these artery clogging ingredients. Even if whey is slightly superior for muscle growth, it is far healthier for your cardiovascular health to use soy.