Review for protein consumption

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Cloud9Fitness
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Joined: Wed Apr 15, 2009 10:19 am

Review for protein consumption

Post by Cloud9Fitness »

I recently gave a talk about fitness nutrition to personal trainers in a continuing education seminar, and addressed several questions on optimal protein supplementation. I’d like to take this time to address some of the key points. Be aware, that the amount of concrete evidence is small, but can provide good information to support your own experience.

What do these studies that look at proteins anabolic effect actually measure?

I have not found a single study that looks for increased muscle mass after supplementation in young adults. The majority of studies look at amino acid concentrations in the blood, in the muscle cell, and amino acid uptake over 4 hours. Newer studies are investigating the changes in DNA translation that occur with muscle protein anabolism. The hope is that this will provide a direct measure of skeletal muscle development. These measures are presumed to estimate muscle growth. Do they? Well, no one knows completely, but it is the best we have right now because a study that measures longitudinal increases in muscle size or strength is likely to be too expensive to conduct.

When should I eat protein?

In the early 2000’s studies were first conducted with amino acid solutions (6 grams of essential amino acids and 35 grams of carbohydrates). The result of these studies was that optimal loading with free amino acids was prior to the workout.

Be careful interpreting this because we typically consume protein sources with a majority of whole proteins (i.e. whey solutions or meats), and not simple free amino acids. Different protein solutions with whole proteins have been evaluated including 20 grams of whey protein alone, milk (8 grams of protein and 12 grams of carbohydrates), and 1-to-1 protein/carbohydrate solutions (0.15grams/kg). The collection of these studies suggest no difference from one hour before or 1 hour after a workout. Again, this is measured with amino acid concentrations in the blood and muscle cells.

These studies do not discuss any abdominal cramping with supplementation prior to exercise, but for the purposes of saturating the muscles with anabolic amino acids it seems you can eat before or after your workout.

How much protein can be ingested at once?

Well, that is a tough question. This question seems to imply that at a certain point your intestines cannot absorb protein above a certain rate. This may be the case (I’m sure we’ve all experienced the side effects of beginning a protein supplement), but the only studies I have been able to find are studies that look at the doses that lead to the maximal concentrations of amino acids in the blood and muscle tissue. The clearest study looked at 0, 5, 10, 20, and 40 grams of egg white protein. 20 grams was the dose where the maximal protein synthesis was measured based on the amino acid concentrations.

The individuals in this study were an average of 22 years of age, 86.1 kg, and BMI of 26 kg/m2.

What type of protein should I eat?

This is where things get a little tricky. It is difficult to rate a protein poorly as long as it provides a complete source of amino acids, 20 grams per serving, and is affordable. Although, it does not appear that difficult for websites to rate the commercial products, but I rarely see any strong explanations for the selections. This is where personal experience can play a large role.

I would like to discuss whey and casein proteins. These proteins are the constant topic of forum discussions. According to these discussions and other website sources, casein is a “slowâ€
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