Which Protein's Are the Most Thermogenic?
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Which Protein’s Are the Most Thermogenic?
Just as we know that not all carbs or fats are treated the same by your body, we also know that proteins are unique in their own right. Casein, the slow protein, and whey a protein does a whole lot more than just enhance protein synthesis. In a new study performed, rats were administered whey protein or casein and put thru a muscle overload protocol. They strapped tiny weights on their backs and electrocuted the floor, which made the rats jump up, similar to if a person was doing weighted jump squats. At the end of the study, it was found that whey protein reduced muscle damage but also enhanced liver antioxidant levels. Interestingly, levels of TBARS, a well-known biomarker of oxidative damage or free radical damage which causes cell destruction, are known to increase in plasma after weight-lifting training; however TBARS was lowered after whey protein consumption. Additionally, whey protein increased total liver glutathione levels, which is a potent antioxidant. Thus, whey protein has potent antioxidant properties both in muscle and in liver. Another interesting finding was that the rats that were administered the exact same amount of protein, yet the whey protein group had larger increases in muscle mass. These results suggest that the potent biochemical anti-oxidant actions of whey protein mediated a reduction in cellular damage to both liver and muscle resulted in enhanced muscle and body weight1. It seems in terms of the anabolic responses whey may have an advantage over casein in that it a potent anti-oxidant, also it has been shown that whey has the ability to inhibit angiotensin II which is a potent vessel constrictor, so you may even get better muscle pumps with whey protein over other protein powders.
Whey protein is not only a ‘fast-acting’ protein as it has been known for years, but it has many more applications for bodybuilding. It may help you get better pumps in the gym. The vascular endothelium is a single-cell layer in blood vessels that influences vascular health and risk of disease by regulating vasoconstriction and vasodilation, blood pressure, blood clotting, etc. Bioactive peptides derived from food, especially milk proteins, exert a wide range of biological actions including decreased blood pressure and improved endothelial function. Milk is a rich source of angiotensin-converting enzyme (ACE) inhibitory peptides. ACE inhibition prevents the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor. Many people with high blood pressure are prescribed ACE-inhibitor drugs to lower blood pressure, but bodybuilders may get a similar effect with whey protein hydrolysates. Most bodybuilders take a nitric oxide (NO) product before exercise to increase muscle pumps, but taking a new and novel whey protein shake may also help with getting better pumps. A researcher from the University of Connecticut investigated a new whey protein hydrolysate and its effects on vasodilation. The active whey supplement was a proprietary peptide isolated from a whey protein hydrolysate (NOP-47, Glanbia Nutritionals, Twin Falls, ID). Subjects consumed one serving a day of NOP-47 or a placebo for two weeks. At the end of the study, researchers found that acute ingestion of NOP-47 significantly increased blood vessel dilation at 30, 60 and 90 minutes, post-ingestion. This means the daily ingestion of a whey protein hydrolysate may be a great way to facilitate blood flow in the gym, as a single serving enhanced vasodilation 90 minutes after consumption. Ok, but what about burning fat, what protein is number one for that category?
What about Thermogenesis? Which Protein Blend is Best?
It has been reported that scientists are finally starting to realize that increasing protein can accelerate weight loss. Protein not only increases energy expenditure but also decreases energy intake through mechanisms that influence appetite control. Their addition to foods, meals, and diets decreases the glycemic index and, when exchanged for carbohydrate, the glycemic load as well, with potential benefits for glucose tolerance and insulin sensitivity. The energy cost of digesting, absorbing, and metabolizing proteins (23%) is greater than that of either carbohydrates (6%) or fat (3%)3. Researchers from Switzerland investigated the thermogenic effects of three proteins: whey protein, casein, and soy protein. The subjects were men and women who consumed a shake consisting of 50% protein, 40 carbohydrates, and 10 percent fats. So which protein came out on top for being the most thermogenic? You guessed it: WHEY PROTEIN WAS MORE THERMOGENIC THAN ANY OTHER PROTEIN7. The consumption of whey protein also resulted in enhanced fat oxidation compared to soy protein. The scientists had a few ideas as to why whey was more thermogenic than the other proteins.
1.) Whey proteins are more rapidly digested and absorbed than is casein and that this improves protein synthesis. Increased protein synthesis has been proposed as one possible mechanism responsible for the increased thermogenesis observed after high-whey protein. The rate of protein synthesis has been observed to be more rapid, 2-fold greater (68% compared with 31%), after the consumption of whey than after that of casein. Ever notice when you eat a big steak, you start sweating! The energy cost of digesting, absorbing, and metabolizing proteins (23%) is greater than that of either carbohydrates (6%) or fat (3%)3. This means the greater increases in protein synthesis resulted in a net greater energetic cost, which increased thermogenesis. It takes energy to increase protein synthesis! Consequently, differences in the rate of protein synthesis after whey, casein, and soy ingestion may explain the small, but significant, differences in thermic effect observed after whey protein.
2.) Also the researchers speculated that increased glucagon secretion may enhance fat oxidation. Whey protein contradictory to what one would expect, promotes fat loss by enhancing the release of glucagon (builds muscle, burns fat). Glucagon stimulates breakdown of glycogen stored in the liver. When blood glucose levels are high, the liver takes up large amounts of glucose. Under the influence of insulin, much of this glucose is stored in the form of glycogen. Glucagon activates hepatic gluconeogenesis. Gluconeogenesis is the pathway by which substrates such as amino acids are converted to glucose. As such, it provides another source of glucose for blood. Glucagon also appears to have a minor effect of enhancing lipolysis of triglyceride in adipose tissue, which could be viewed as an addition means of conserving blood glucose by providing fatty acid fuel to most cells. For example, Glucagon-like peptide-2 (GLP-2) is a nutrient-regulated intestinotrophic hormone derived from proglucagon in the distal intestine. GLP-2 has been found to be stimulated after whey protein consumption4. Another study insulin and glucagon responses increased with increasing protein load for whey protein and casein, but the effect was more pronounced for glucagon after whey consumption. A higher dose of protein or its hydrolysate will result in a lower insulin: glucagon ratio, an important parameter for the control of postprandial substrate metabolism. Another study found that insulin and glucagon responses to whey protein resulted in lower respiratory quotients, indicative of increased fat oxidation, after a breakfast meal containing whey protein than after meals containing casein or soy5. Whereas it is tempting to suggest that the elevated glucagon concentrations observed after whey consumption may have interfered with insulin’s antilipolytic effects and permitted fat oxidation to continue at, more or less, fasting concentrations, evidence for the lipolytic effects of glucagon after whey protein consumption are reported6. This is just another reason to throw some whey protein powder in your shaker cup when coming home from the gym!
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