Is Isolate Protein Best After Workouts?

Consuming a whey isolate protein drink following a workout preserves muscle and aids in recovery. In a 10-week study of recreational bodybuilders, a group given whey isolate made greater improvements in strength, increased lean mass and reduced fat mass compared to a group given casein, researchers reported in the October, 2006 "International Journal of Sport Nutrition and Exercise Metabolism." Whey isolate and casein are protein supplements that derive from milk.

A woman is packing a protein shake into her shaker bottle. (Image: gpointstudio/iStock/Getty Images)

Background

Whey isolate protein helps to prevent breakdown of muscle tissue that can occur during recovery from a workout. Muscle growth occurs as a result of the body's repair of minute tears in muscle fibers following a workout. Most Americans receive adequate dietary protein and don't require supplementation. Athletes, bodybuilders and people in training for endurance events or seeking to improve their ratio of muscle to fat can benefit from supplemental protein.

Advantages

Whey isolate protein is convenient to buy, mixes well, comes in many flavors and has a long shelf-life in its powdered form. It combines well with milk, juice, fruit and nutritional supplements in your blender for a nutritious post-exercise drink. Adding ice to the blender drink results in a milk shake consistency, and you can add cocoa powder or flavored extracts such as vanilla or peppermint for variety. In its powdered state, whey protein powder isn't vulnerable to spoiling, so you can carry it along in a shaker bottle to the gym or for an outdoor workout, and add water when you're ready to drink it.

Benefits

One of the reasons whey isolate is recommended as a post-workout protein source is that it is easy for most people to digest. Whey is a byproduct of the cheese-making process. Whey isolate results from removing fat and lactose from the whey. Some adults have difficulty digesting lactose, a naturally occurring milk sugar. Whey isolate offers a high concentration of protein and is a richly supplied with branched chain amino acids -- components of protein used as energy during strenuous activity. Whey isolate offers rapid replenishment for your muscles after working out. Kosowski says whey isolate is an ideal choice for post-workout protein.

Considerations

Whey isolate should be used as a supplement, not as a primary source of nutrition. Whole food sources of protein such as fish, poultry, eggs and meat provide additional nutrients.

Combining sources of protein in a post-workout shake offers longer-lasting energy for your muscles. Although whey provides the advantage of quick protein uptake, it doesn't provide a sustained protein source. Combining protein sources in your post-workout drink-- such as whey isolate and casein or egg -- offers longer-lasting fuel. Combine whey protein isolate with carbohydrate, such as a piece of fruit, for the best supply of nutrients for recovery after your workout.