Natural bodybuilders, which means those who refuse to use any type of pharmaceutical aid to build muscle mass, are constantly searching for food supplements and other natural means of increasing their bodybuilding gains. Several studies show that you can manipulate your hormonal
flow through diet. One way of doing this involves increasing muscle protein synthesis. Hormones that have the ability to enhance this process include testosterone, growth hormone, insulin and insulin like growth factor I, or IGF-I. Just the act of lifting weights can increase
your supply of most of these hormones, with the notable exception of insulin, which is usually depressed during exercise and for a good reason. Although insulin has potent effects in terms of promoting amino acid entry and subsequent protein synthesis in muscle, it also lowers
blood glucose, or sugar, rapidly.
Since glucose serves as a source of energy during exercise, it's obviously not in your body's best interest to have a heavy insulin flow that clears circulating blood glucose during exercise. Even so, some researchers, such as Tom Fahey, Ph.D., of California State University, Chico, believe that elevating insulin during exercise can have a potent anabolic effect in muscle. He suggests drinking large quantities of a carbohydrate-and-protein drink during training to make this happen. While it sounds like a good idea, many bodybuilders would not enjoy drinking as much fluid during the course of a workout as Fahey suggests.
A more practical way to get similar beneficial effects involves elevating your insulin level after a workout. This has two immediate effects: t) increased synthesis of muscle glycogen, the primary fuel for weight training; and 2) increased entry of amino acids into muscle for use in protein synthesis reactions. Both protein and carbohydrate can elevate insulin output if ingested after a workout, but carbohydrate has a more potent effect. If you combine protein and carbohydrate, however, the insulin output is greater than if you take in either nutrient alone.
Besides promoting amino acid entry and protein synthesis in muscle, insulin also indirectly boosts an anabolic effect by stimulating the flow of additional hormones. For example, by lowering blood glucose levels, it induces an increased output of growth hormone, which, in turn, stimulates the liver to synthesize still another anabolic hormone, IGF-l. While growth hormone itself only lasts about 60 minutes before it's degraded in the liver, the growth hormone-promoted output of IGF-1 occurs about three to six hours after the initial growth hormone surge. IGF-1 doesn't actually peak in the blood until 16 to 28 hours after it's released. This is significant because many researchers believe that most of growth hormone's beneficial effects on muscle occur through its stimulation of IGF-I. Recently, researchers from the University of Texas at Austin decided to see if they could manipulate the body's anabolic hormone flow after weight training through diet. Nine experienced male bodybuilders consumed one of three drinks water, a carbohydrate drink or a carbohydrate-and-protein combination-both immediately and two hours after a workout.
As expected, the exercise itself elevated lactate, glucose, testosterone and growth hormone levels. Of the three drinks, however, the protein carbo combo caused the greatest elevation of insulin 30 minutes after the workout. In animals exercise increases muscle protein synthesis for up to 24 hours, hut after a certain point muscle protein begins to become degraded, a catabolic effect. While in creased insulin levels after a workout won't prevent this degradation by stimulating protein synthesis, it may offset much of it.
In the experiment with humans described above, the insulin increase caused by the protein and carb drink also promoted a high growth hormone flow five to six hours after the workout. No increase in 1GB-I occurred, however, which is strange considering the effect that growth hormone has on 1GB-I production in the liver. The researchers speculated that an increased 1GB-I flow might have occurred almost a day after the initial increased growth hormone spike. As for testosterone, the workout elevated its secretion, but the subjects' testosterone levels nosedived immediately after and remained low for six hours. In the subjects who drank only water after the workout, testosterone levels returned to normal and remained stable. In those who drank either of the nutrient drinks or ate a meal, testosterone levels decreased. To test whether the nutrient drinks had somehow lowered testosterone levels after the workout, the researchers measured the output of a pituitary hormone, called Latinizing hormone, or LH, that controls testosterone production. The LH levels were normal. This finding led the researchers to speculate that the lowered testosterone occurred as a result of increased clearance from the blood. Other studies have shown that meal composition can affect blood testosterone levels, including one which showed that a high-fat meal lowers testosterone levels by 40 percent for four hours after it's eaten.
The researchers from the University of Texas concluded their study by noting that "carbohydrate and carbohydrate/protein supplements stimulated an environment favorable for muscle growth throughout the body by increasing plasma concentrations of growth hormone and insulin during recovery". In practical terms, this means that consuming a carbohydrate and protein drink within two hours after a workout should promote an optimal flow of anabolic hormones conducive to muscular growth. The drink used in the study provided 1.06 grams of carbohydrate per kilogram, or 2.2 pounds, of body-weight, and 0.41 grams of protein per kilogram, although 1.0 grams per kilogram of protein would probably be more beneficial.