Month in and month out, one of our top-selling products is the Nature's Best Isopure Protein supplement. A few key features keep this line selling better than the hundreds of products against which it competes. In terms of protein, it's hard to beat Isopure with its sky-high 50 grams per serving, all of which is from 100% premium whey protein isolate (WPI). Because it's made from pure WPI, Isopure is virtually lactose-free and ridiculously low in carbs (0g) and fat (1g). Isopure is lactose and aspartame-free also (sucralose aka Splenda is used). Isopure makes a good protein shake if that's all you want, but works equally well as the basis for a meal replacement shake since Isopure contains essential vitamins and minerals. In that case, be sure to make the shake with non-skim milk or consume some healthy fats to help you absorb all of Isopure's vitamins.