Information about the Protein Supplement Muscle Milk
Protein supplements are big business. One brand that has gotten a lot of attention lately is Muscle Milk, which is touted by some professional athletes. Muscle Milk is available as a powder, a ready-to-drink shake and a bar, to consume before, during or after a workout—or any time, really—to increase strength and speed recovery from exercise. If you engage in endurance exercise or serious strength training, you do have slightly higher protein needs. But do you need a protein supplement, especially if you're just a casual exerciser? And is Muscle Milk, in particular, any better than other products?
What's in Muscle Milk?
A serving of Muscle Milk powder (two scoops, mixed in 10 to 12 ounces of water) has 300 calories, 32 grams of protein, 12 grams of fat (half saturated fat), 16 grams of carbohydrates, 5 grams of fiber, and an array of vitamins and minerals.
A 14-ounce ready-to-drink Muscle Milk shake has 220 to 240 calories, 25 grams of protein, 9 grams of fat (mostly unsaturated), and 10 to 14 grams of carbohydrates. The proteins are basically in the form of whey and casein (as found in milk), while the fats are medium chain triglycerides (MCTs) and sunflower/safflower and canola oils.
Whey and casein—special proteins? Protein provides the amino acids needed to build and repair muscle tissue. A 2009 review in the Journal of the American College of Nutrition concluded that a combination of whey and casein protein, which have different digestion rates, produces "superior gains in muscle mass compared with a single protein source or blends of protein with similar digestion rates." Still, as this and other research also points out, consuming any type of protein stimulates muscle protein synthesis, and no one knows what an optimal protein blend really is. There is nothing magical about the proteins in Muscle Milk, despite the implications on its website.
Special fats? Rather than being stored as fat, MCTs can be used as a rapid source of fuel. This spares carbohydrate stores and, in theory, allows an athlete to work out harder and longer before reaching exhaustion. But study results have been mixed as to whether MCTs improve exercise performance, and it's unclear whether long-term intake is beneficial or what effects MCTs have in recreational athletes.
Muscle Milk also contains highly unsaturated oils, which supply "essential fatty acids." But we already get plenty of these fats in our diet. We don't need more fat calories from a supplement. Moreover, these fats delay gastric emptying (how quickly foods leave the stomach and enter the small intestine) and may thus contribute to stomach upset in exercisers and actually be counterproductive when you are trying to replenish carbohydrates and fluids.
What's in a name? Though the website for Muscle Milk doesn't say this outright, it implies that the protein and fat profile of the supplement resembles that of human breast milk and that somehow this is particularly good for athletic performance. Infants, of course, thrive on breast milk, but it's not clear what relevance this has for athletes.
Muscle Milk Bottom Line
You don't need Muscle Milk—or any protein supplement—especially if you are a recreational athlete or casual exerciser. Most active people easily meet their protein needs through diet alone, as long as they get enough calories to maintain their weight and eat a variety of healthful foods. To aid recovery from intense exercise, just finish your workout with any snack high in protein and carbs—say, a yogurt-and-fruit smoothie, a bowl of cereal with low-fat or nonfat milk, or a peanut butter/banana sandwich with a cup of milk. Like many protein supplements, Muscle Milk is also expensive—a 12-pack of the bottles costs $40 to $50.
Source: Originally published in The University of California, Berkeley Wellness Letter (January 2011)