GNC’s Total Lean product line offers a number of weight management supplements, including Lean Shake. Lean Shake is meant to be a meal replacement, it is a supplement that is meant to be mixed with water. One serving of Lean Shake contains 180 calories, which is far fewer than the average meal. Even though a lot of meal replacement shakes are fairly high in protein, Lean Shake contains just 9g of protein per serving, with 30 g of carbs and 2g of fat. Lean Shake is also very high in fiber, as it contains over 8g per serving. Fiber can help in weight loss as it can help you feel fuller.