Maximize performance, lean mass, hard muscles, increased stamina; these and much more have been promised on labels of tons of supplements and ads of new products as recovery aids or pre-workout foods. It is difficult to determine if these products are beneficial since one can practically find some research somewhere to support just about any claims these days. In fact, I find it rather dubious to even rely on scientific journals because they too receive funding from companies with biased interest in the outcome. Not to sound too cynical, but I just read an article in a bodybuilding magazine and became disgusted by the author’s inability to support his information, which was based on two scientific references. With some basic and rudimentary understanding of the needs of the body following exercise, individuals, then, can make a better choice when it comes to selecting their fuel source.
Glycogen is one of the main sources of fuel for exercise, which is simply a starch made of glucose molecules that can be hydrolyzed readily. It is stored directly in the muscle fibers generally in the range of 1500-2500 kcal. A most important aspect of muscle glycogen hydrolysis is that it can be quickly activated to resynthesize ATP at high rates. This rate can not be maintained for more than 60-90 seconds because lactic acid accumulates in muscles and eventually inhibits excitation-contraction coupling. Your liver also stores glycogen (240kcal) and releases it into the blood stream as glucose primarily to maintain blood glucose concentration while exercising muscles are outpacing glucose from the blood. Once you have depleted your muscle glycogen and can’t maintain blood glucose levels to meet the demand placed on your muscles due to exercise, you will hit the “wall”. It is important to eat carbohydrates within a few hours after exercising to replenish the glycogen stores. This increases levels of glucose in your blood stream and causes insulin to be secreted from the pancreas, which further triggers the muscles to suck up glucose and form glycogen.
If you are a conditioned athlete, your muscles have adapted to making more enzymes for better endurance, which means more efficient or better able to generate ATP. Your muscles have more effective contractile machinery to generate more power. This is accomplished by synthesizing new proteins. Weightlifting and other strenuous activities such as sprinting stimulate an increase in muscle mass within the fibers by altering the balance between synthesis and degradation of specific proteins. So it makes sense to eat protein after exercise to supply amino acids to optimize tissue rebuilding. Consuming protein may also be beneficial by further increasing insulin secretion, thus accelerating glucose uptake and glycogen formation in muscles. Taking antioxidants such as vitamin C and E are also advantageous.
Utilizing this knowledge, it is no wonder that recovery aids are composed of a blend of carbohydrates and protein, with added vitamins such as A, B6, B12, C, D, E; minerals such as calcium, sodium, potassium, and iron; and even grapeseed extract and green tea extract. Obviously, the products vary in their ratios of carb to protein, and the types and levels of vitamins and minerals. They come in liquid, powder, pills, or bars and can end up costing you more than you can benefit from their claims.
The more reputable companies will fund researchers to test their products in carefully controlled settings, and results may be published in peer-reviewed scientific journals. Unfortunately my exhaustive search of the scientific literature reveals that only a few studies have been published on these products, despite the ads heralding university research demonstrating their effectiveness. Some research has shown that specific products can enhance recovery, while other research has shown that same product does not work better than placebo. Because the studies are designed so differently as far as type and length of exercise, and timing of ingestion, they can be difficult to compare.
So the bottom line is that more research is needed before any conclusion can be reached. As for the readers of this article, should you shell out money for these products? I think if you typically have no appetite after a long run, or a hard workout, recovery products offer an alternative to help you refuel. The problem is that many of them contain large number of calories and can lead to weight gain if used often or combined with meals. If you eat a regularly after exercise and maintain a well balanced diet, then I think they are an unnecessary expense. Some athletes swear by these products, as I am sure many of our writers that live off of supplements instead of food, do as well. However, many dietitians suggest that basic carbohydrate and protein meals such as rice and beans, or fruit and cottage cheese will do just as well. I recommend trying a couple of alternatives and find the one that works best for you.