Is Protein Timing Overplayed?

Several studies have pointed to the importance of protein timing—taking in protein or amino acids close to a workout—which is thought to diminish excessive muscle protein breakdown during training. The increased blood flow that results from training may boost amino acid entry into muscle. One study of older men who got a supplement of 10 grams of protein, seven grams of carbohydrate and three grams of fat found that when it was taken immediately after training, that combination resulted in significant muscle gains. Those who took the same supplement two hours after the workout got no apparent benefits.

In another study younger men, aged 21 to 24, got 40 grams of whey protein isolate and 43 grams of glucose either just before and after training or in the morning and evening. Those who took the supplement close to the workouts experienced far more gains in muscle size and strength than the others.

These studies featured either untrained or recreational subjects. A new study featured college football players and powerlifters. Although the authors suggest that this makes their findings more relevant to experienced weight trainers, football players and powerlifters don’t train the same way bodybuilders do. In any case, the researchers set out to determine whether there is any advantage to taking a protein supplement before and after workouts compared to other times in relation to size and strength gains.

The study lasted for 10 weeks and involved 33 men divided into two groups, with one group taking a protein supplement in the morning and evening, and the other group taking it just before and immediately after training. Another seven men, acting as a control group, didn’t use any protein supplements. The subjects were tested for changes in strength, power and body composition. All three groups showed improvements in one-rep-maximum bench press and squat strength after 10 weeks, but there were no significant differences between the groups. None showed any changes in body mass or percentage of bodyfat.

Based on those findings, the authors suggest that taking in more protein than the required 1.6 grams per kilogram of bodyweight doesn’t yield additional muscle gains, regardless of when you get the protein. They did note, however, that the subjects met the requirements for protein intake suggested for strength athletes and also underscored the idea that strength athletes benefit from getting more protein. The supplement they used was low in carbohydrate. Combining protein with carbohydrate leads to an increased insulin release, which in turn leads to greater amino acid uptake into muscle and provides an anticatabolic effect. The subjects also took in fewer than the optimal number of daily calories, which would limit muscle size gains to an extent.

In a study published in a different journal, the same authors tested the effects of a protein supplement on exercise recovery and found that taking one before and after training enhanced recovery for 24 and 48 hours after the workout. While the researchers didn’t find any notable changes in hormone status, they did note that a measure of exercise-induced muscle damage decreased in those on the supplement but not in those getting the placebo. That, they suggest, may have resulted from an anticatabolic effect of the supplement related to upgraded muscle protein synthesis.

Another study tested whether taking a combination of essential amino acids and carbohydrate prior to a weight-training workout would boost muscle protein synthesis afterward. Twenty-two young, healthy subjects were observed before, during and two hours after a leg-training workout. One group fasted before the workout, while the other group got essential amino acids and carbs one hour prior to training. Those in the amino-and-carb group showed an immediate rise in muscle protein synthesis, which dropped to resting level during the workout and remained unchanged an hour after it. Those in the fasting group showed a drop in muscle protein synthesis during the workout, followed by a rise an hour later. By the two-hour posttraining mark, both groups showed a 50 percent increase in muscle protein synthesis.

During training, muscle protein synthesis is repressed through the increased expression of a protein called AMPK, an energy sensor in muscle that encourages the use of fuels such as fat. Taking the amino acid-and-carb combo before training prevented the usual drop in muscle protein synthesis that occurs during exercise, but it didn’t stimulate it either during or after exercise. AMPK counts were similar in both groups. On the other hand, the posttraining rise in muscle protein synthesis was delayed by an hour in the amino group. That may owe something to the rise in muscle protein synthesis right after the supplement was taken and may have resulted in a small refractory effect after the workout. Based on those findings, the authors suggest that it is more effective to take a supplement containing amino acids and carbs following a workout than before it.

—Jerry Brainum
www.JerryBrainum.com

References

Hoffman, J.R., et al. (2009). Effect of protein-supplement timing on strength, power and body composition changes in resistance-trained men. Int J Sport Nutr Exerc Metab. 19:172-85.

Hoffman, J.R., et al. (2009). Effect of a proprietary protein supplement on recovery indices following resistance exercise in strength/power athletes. Amino Acids. In press.

Fujita, S., et al. (2009). Essential amino acid and carbohydrate ingestion prior to resistance exercise does not enhance postexercise muscle protein synthesis. J Appl Physiol. In press.