First, while there is an abundance of acute data, controlled, long-term trials that systematically compare the effects of various post-exercise timing schemes are lacking. These findings suggest that older subjects require higher individual protein doses for the purpose of optimizing the anabolic response to training. In contrast, Yang et al. found that elderly subjects displayed greater increases in MPS when consuming a post-exercise dose of 40 g whey protein compared to 20 g. Illustrating this point, Moore et al. found that 20 g whole egg protein maximally stimulated post-exercise MPS, while 40 g increased leucine oxidation without any further increase in MPS in young men. However, infusion-based studies in rats 78,79 and humans 80,81 indicate that the postprandial rise in MPS from ingesting amino acids or a protein-rich meal is more transient, returning to baseline within 3 hours despite sustained elevations in amino acid availability. Layman estimated that the anabolic effect of a meal lasts 5-6 hours based on the rate of postprandial amino acid metabolism. At the end of the study period, muscle CSA was significantly greater in the protein-supplemented group compared to placebo or control. The study was limited by its use of DXA to assess body composition, which lacks the sensitivity to detect small changes in muscle mass compared to other imaging modalities such as MRI and CT . At the end of the study period, total body mass, fat-free mass, and thigh mass was significantly greater in the protein-supplemented group compared to the group that received dextrose. Strength training damages the muscles, which causes them to repair and grow. If you’re trying to build muscle, strength training is the best way to do it. For the goal of maximizing rates of muscle gain, these findings support the broader objective of meeting total daily carbohydrate need instead of specifically timing its constituent doses. One of many possible examples involving a 60-minute resistance training bout could have up to 90-minute feeding windows on both sides of the bout, given central placement between the meals. The combination of these factors facilitates the rapid uptake of glucose following an exercise bout, allowing glycogen to be replenished at an accelerated rate. In addition, there is an exercise-induced increase in the activity of glycogen synthase—the principle enzyme involved in promoting glycogen storage . Exercise enhances insulin-stimulated glucose uptake following a workout with a strong correlation noted between the amount of uptake and the magnitude of glycogen utilization . Considering the totality of evidence, maintaining a high intramuscular glycogen content at the onset of training appears beneficial to desired resistance training outcomes. Other researchers have displayed a similar inverse relationship between glycogen levels and proteolysis . Lemon and Mullin found that nitrogen losses more than doubled following a bout of exercise in a glycogen-depleted versus glycogen-loaded state. Several pathways that have been identified as particularly important to muscle anabolism include mammalian target of rapamycin (mTOR), mitogen-activated protein kinase (MAPK), and various calcium- (Ca2+) dependent pathways. MacDougall et al. demonstrated that a single set of elbow flexion at 80% of 1 repetition maximum (RM) performed to muscular failure caused a 12% reduction in mixed-muscle glycogen concentration, while three sets at this intensity resulted in a 24% decrease. Some have claimed that such timing strategies can produce dramatic improvements in body composition, particularly with respect to increases in fat-free mass . The study consisted of a full-body routine that ran on three-week sessions on nonconsecutive days for ten weeks. The subjects of the study were all paired based on their strength in the squat and bench press exercises. Moreover, the post-exercise rise in MPS in untrained subjects is not recapitulated in the trained state , further confounding practical relevance. Adding yet more incongruity to the evidence, Tipton et al. found no significant difference in net MPS between the ingestion of 20 g whey immediately pre- versus the same solution consumed 1 hour post-exercise. A limitation of the study was that training involved moderate intensity, long duration aerobic exercise. Protein synthesis of the legs and whole body was increased threefold when the supplement was ingested immediately after exercise, as compared to just 12% when consumption was delayed. Levenhagen et al. demonstrated a clear benefit to consuming nutrients as soon as possible after exercise as opposed to delaying consumption. While nutrient timing may have situational relevance, recent research underscores that immediate post-workout intake is not universally critical for optimizing muscle hypertrophy or recovery. The anabolic window concept originated from early studies suggesting protein and carbohydrate intake within 30 to 60 minutes post-exercise optimizes muscle growth. No significant differences in muscle strength or hypertrophy were noted between groups at the end of the study period indicating that post exercise nutrient timing strategies do not enhance training-related adaptation. Another purported benefit of post-workout nutrient timing is an attenuation of muscle protein breakdown. The anabolic state theory suggests that it is critical to consume proteins and carbohydrates immediately after resistance training to increase muscle protein synthesis, reduce muscle protein breakdown, and replenish glycogen levels in the muscle. This includes muscle proteins that rapidly turn over or have been damaged. This balance is called net muscle protein balance (NBAL). After strength training, your body is in an anabolic state. The anabolic window theory is based on your body’s anabolic response. Several researchers have made reference to an anabolic "window of opportunity" whereby a limited time exists after training to optimize training-related muscular adaptations. The results of this study showed that the protein consumption before the workout and after the workout had shown similar effects on all the subjects studied. To increase mass muscle size, changes depend on myofibrillar proteins and MPB would need to target these proteins specifically. Since eating protein and carbohydrates immediately after exercising is known to reduce MPB, it is also assumed that this will increase lean muscle mass by increasing the net protein balance. As we exercise, glycogen is broken down into glucose and provides the needed, immediate energy for cells. ATP is a necessity to the body, especially during exercise when a constant supply of energy is required.
