Some bodybuilders never use protein supplements, preferring instead to get all their protein from food sources, such as meat, fish and eggs. Their view is backed by most mainstream dietitians, who note that it’s not difficult to get all the protein you need to build muscle just from eating food.
In fact, most people eat more protein than they need. Since protein contains four calories per gram—the same as carbohydrate—it’s possible for those who are sedentary to gain some bodyfat by eating large amounts of protein, especially if they also eat too much fat and carbohydrate. That scenario is unlikely in those who are physically active. Their excess protein is oxidized in the liver, with the nitrogen portion converted into urea and then excreted through the kidneys.
So no one argues that it’s easy to get enough protein from various high-protein foods, but does that mean that additional supplements aren’t necessary? For one thing, most protein foods also contain appreciable amounts of either fat and/or carbohydrate. That is a concern for those seeking to lose bodyfat, since every calorie does count—contrary to what some so-called experts say. With concentrated protein supplements you get a source of high protein minus the excess calories. In addition, some people either won’t or can’t eat several high-protein meals a day. Having a source of protein that they can eat on the go is not just a convenience, it’s a necessity.
In recent years milk proteins have been shown to rate the highest in biological value over other sources, such as meat, soy and even eggs. The two primary proteins in milk are casein, which accounts for 80 percent of milk protein, and whey, which is the remaining 20 percent.
Anyone who has kept up with the research on milk protein knows that the two have different absorption properties. Whey is rapidly absorbed, since it stays in solution during the digestive process. Whey uptake peaks at about 60 minutes after ingestion and then declines to baseline after about 90 minutes. The advantage is that the rapid absorption also favors a speedy release of essential amino acids into the blood and muscle, which encourages muscle protein synthesis, the cornerstone of muscle growth.
In contrast, casein curdles in the stomach after you eat it. It looks like cottage cheese, which is mostly casein. The curdling effect favors a more sustained release of aminos over a period of up to seven hours. Initial research that compared whey and casein found that the rapid uptake and release of essential aminos from whey more reliably stimulated muscle protein synthesis, while the slow release of casein promoted a steady trickle into the blood over a longer time, which favored a blunting of muscle catabolism, or breakdown.
It’s not hard to understand how the properties of the two milk proteins significantly benefit bodybuilding trainees; however, there’s far more to milk protein than being a superior source of amino acids. Research shows that besides casein and whey, there are smaller proteins, known as bioactive peptides, in milk that may provide amazing health benefits. I say may because the research is still in its infancy, and all the data haven’t been collected yet.
The scientific method decrees that a finding must be replicated numerous times and under varied conditions before it’s officially accepted as fact. Thus far, most of the research on milk bioactive peptides has involved animals. The good news is that the same mechanisms that allow them to produce their beneficial effects in animals also exist in the human body.
Bioactive peptides are small chains of amino acids linked in a specific formation. While casein contains some, whey is a powerhouse source. Just a day before I wrote this a new study found that one of those peptides has potent protective effects against cancer. Earlier studies showed that because of whey’s high content of the amino acid cysteine, it can be a precursor of glutathione, a major antioxidant in the body. A form of whey is used to prevent the loss of lean mass in cancer patients and those afflicted with HIV.
More pertinent to bodybuilders is the effect of whey on body composition. The process of digesting and absorbing proteins is energy intensive; that is, it uses calories. In fact, it uses more calories to digest and absorb proteins than either fats or carbs. Calories not used in power movement or muscle function are diverted to heat production, a process known as thermogenesis. That term may be familiar to those who use various “fat-burning” supplements, since nearly all of them work by promoting a thermogenic effect: converting fat calories into heat.
Compared to other proteins, such as casein and soy, whey has a greater thermogenic effect, which is attributed to the rapid protein synthesis it triggers, as mentioned above. The rate of protein synthesis produced by whey is twice that of casein, again because of whey’s rapid release of amino acids. The branched-chain amino acid leucine is considered the key amino in muscle protein synthesis, and whey contains 50 to 75 percent more leucine than other protein sources.
Whey may also aid fat loss through its effect on insulin. Many people are confused about insulin. Some worry that it can trigger excess fat production in the presence of excess calories, especially from carbohydrates, but insulin has other properties that are beneficial. It’s also required for cellular uptake of glucose, the elemental form of sugar in the blood. Without proper insulin function, you would have diabetes. Also on the plus side, insulin is known to favor amino acid uptake in muscle and prevent catabolism. In addition, it stimulates the activity of enzymes that produce glycogen from carbs and other sources. Glycogen is required for full muscle recovery after training and also powers anaerobic training, which includes bodybuilding workouts.
Milk protein is a potent stimulus for insulin release, but it’s not a bad thing. The release is within physiological limits and so does not encourage bodyfat synthesis. One study found that only 20 grams of whey protein stimulated enough insulin release to significantly lower elevated blood glucose. In another involving diabetics—who lack proper insulin activity—the subject were fed meals high in rapidly absorbed and digested carbohydrates, but some also got whey at the same meal. Adding whey to the carb meal led to a 57 percent greater insulin release and a smaller drop in glucose after the meal.
Although it isn’t precisely known how whey favors an insulin release, its amino acid content, particularly the high leucine mentioned above, is a chief suspect. Leucine alone is known to stimulate insulin release in the pancreas through at least two mechanisms, one of which involves a metabolite of leucine.
More recent research shows that whey also affects insulin release by promoting the release of gut peptides known as “incretins.” In one study, consuming a whey drink stimulated an 80 percent greater release of gastric inhibitory peptide, which itself encourages insulin release. Whey also promotes the release of another gut peptide called glucagon-like peptide-1 that encourages insulin release and has the side benefit of curtailing appetite. That may explain how whey helps suppress appetite during a diet. Both of the peptides are degraded in the gut via an enzyme that is blunted by whey protein. Recently, a few drugs that treat diabetes were released, all of which block the same enzyme. Unlike whey, however, the drugs are linked to pancreatitis, an inflammation of the pancreas, as well as possible pancreatic cancer, the most deadly cancer of all.
In relation to appetite, it’s once again the fast amino release induced by whey that produces an appetite-suppressive effect. Studies with animals show that leucine can rapidly enter the brain, where it induces appetite suppression. The mechanism is thought to involve a blunting of the release of appetite-stimulating peptides in the brain. The release of insulin induced by whey also potently depresses appetite, mostly because whey blunts the release of ghrelin, a protein that is the most potent appetite-stimulating substance in the body. Ghrelin rises a few hours after a meal and produces intense hunger sensations. It’s not hard to understand how controlling it would aid dieting efforts.
So the combination of a controlled insulin release, the stimulation of gut peptides that promote insulin and the blunting of proteins in the brain that trigger appetite make whey a valuable asset if you’re looking to build muscle and lose excess bodyfat.
By Jerry Brainum