Without question, protein is the king of all nutrients. It provides the building blocks for enzymes and hormones, enables nerve and brain cells to effectively communicate with one another, and fosters the repair and growth of muscle tissue. Every cell in your body contains protein; life could not go on without it.
The consumption of protein, however, is perhaps the most controversial of all nutritional topics. Unfortunately, many nutrition professionals have not kept abreast of recent research and continue to espouse outmoded theories on the subject. This has led to a host of myths that, in turn, have been taken as gospel by the general public. The following are some of the more common misconceptions about dietary protein intake:
Myth: High protein diets make you fat.
Fact: There is no doubt that eating too much protein will pack on the pounds-but so will eating too many calories from carbs or fat! Weight gain is governed by the law of thermodynamics: if you consume more calories than you expend, you’ll gain weight. Consequently, it’s not protein per se that causes weight gain; it’s an over consumption of calories. No matter what you eat, if you consume too much of it, you’ll ultimately end up getting fat.
In actuality, if you were to eat a meal containing only protein, carbs, or fat, the protein meal would cause the least amount of weight gain. You see, a large percentage of calories from protein are burned off in the digestion process. This is called the thermic effect of food. Of all the macronutrients, protein has the highest thermic effect, burning off approximately 25 percent of protein of the calories consumed . In comparison, only 15 percent of the calories from carbs are burned off in digestion; fat has virtually no thermic effect whatsoever . Thus, all other things being equal, a high protein diet would be less likely to cause fat deposition than either a high carb or high fat diet.
Moreover, unlike carbs, protein doesn’t stimulate a significant insulin response. Insulin is a storage hormone. While its primary purpose is to neutralize blood sugar, it also is responsible for shuttling fat into adipocytes (fat cells). When carbohydrates are ingested, the pancreas secretes insulin to clear blood sugar from the circulatory system. Depending on the quantities and types of carbs consumed, insulin levels can fluctuate wildly, heightening the possibility of fat storage. Since protein’s effect on insulin secretion is negligible, the potential for fat storage is diminished
What’s more, the consumption of protein tends to increase the production of glucagon, a hormone that opposes the effect of insulin. Since a primary function of glucagon is to signal the body to burn fat for fuel, fat loss, rather than fat gain, tends to be promoted.
Myth: High protein diets are damaging to your kidneys.
Fact: The metabolism of protein entails a complex sequence of events in order for proper assimilation to take place. During digestion, protein is broken down into its component parts, the amino acids (via a process called deamination). A byproduct of this occurrence is the production of ammonia, a toxic substance, in the body. Ammonia, in turn, is rapidly converted into the relatively non-toxic substance urea, which is then transported to the kidneys for excretion.
In theory, a large build-up of urea can overtax the kidneys, impairing their ability to carry out vital functions. This has been supported by studies on people with existing renal disease. It has been well documented that a high protein diet exacerbates uremia (kidney failure) in those on dialysis (i.e. the artificial kidney machine), while a low protein diet helps to alleviate the condition . Proteinuria and other complications also have been observed in this population .
However, there is no evidence that a diet high in protein has any detrimental effects on those with normal renal function. Healthy kidneys are readily able to filter out urea; any excess is simply expelled in the urine. Consider the fact that, over the past century, millions of athletes have consumed large quantities of protein without incident. Surely, if high protein diets caused kidney disease, these athletes would be all on dialysis by now. Yet, in otherwise healthy individuals, not one peer-reviewed journal has documented any renal abnormalities due to an increased intake of protein.
As an aside, it is beneficial to drink ample amounts of fluids when consuming a high protein diet. This helps to flush your system and facilitates the excretion of urea from the body. For best results, a daily intake of at least a gallon of water is recommended, drinking small amounts throughout the day.
Myth: High protein diets result in an inordinate intake of unhealthy saturated fat.
Fact: The majority of Americans get their protein from red meat and dairy products-foods that have a high percentage of saturated fat. High fat protein sources such as bacon, T-bone steaks, hard cheeses, and whole milk are staples of the American diet. What’s more, ketogenic “diet gurus” like Dr. Robert Atkins encourage the consumption of these products, touting them as viable dietary options . Accordingly, high-protein diets have become synonymous with the intake artery-clogging fats.
However, there is no reason that a high protein intake must be derived from cholesterol-laden foods. There are many protein sources that contain little, if any, saturated fat. Skinless chicken breasts, egg whites, and legumes are all excellent, low-fat protein choices. By simply choosing the “right” foods, a high protein diet can be maintained with minimal effect on fat consumption.
In addition, it is important to realize that certain fats, specifically the unsaturated, Omega fatty acids, are actually beneficial to your well being, aiding in the absorption of fat-soluble vitamins and facilitating the production of various hormones, cell membranes and prostaglandins. These “essential” fats cannot be manufactured by the body and hence must be obtained through nutritional means. Cold water fish (such as salmon, mackerel and trout), tofu and peanut butter are protein-based foods that also are terrific sources of essential fats. Their consumption has been shown to have a positive impact on cardiovascular health and reduces the risk of several types of cancers.
Myth: High protein diets are unnecessary for athletes.
Fact: If you believe the United States Department of Agriculture (USDA), there is no difference in protein requirements between athletes and couch potatoes. This is reflected in the RDA for protein, which is the same for all individuals regardless of their activity levels.
However, contrary to the USDA position, studies have shown that athletes do indeed require more protein than sedentary individuals . When you exercise, protein stores are broken down and used for fuel (via a process called gluconeogenesis). The branched chain amino acids (BCAAs), in particular, are preferentially mobilized as an energy source during intense training, as are alanine and glutamine. It has been shown that when athletes consume a low protein diet (equivalent to the RDA for protein), there is decreased whole body protein synthesis, indicating a catabolism of muscle tissue.
On the other hand, it is imprudent to ingest enormous quantities of protein in hopes that it will improve athletic performance. Bodybuilders often subscribe to this “more is better” philosophy and gorge themselves with protein-rich foods and supplements (one popular bodybuilder claims to ingest as much as 1000 grams of protein a day!). Unfortunately, the body only has the capacity to utilize a limited amount of protein. Once the saturation point is reached, additional protein is of no use to the body and is either used as energy or converted into triglycerides and stored as fat. In general, optimal protein synthesis can be achieved by consuming one gram of protein per pound of bodyweight. Thus, for maximizing strength and performance, a 150-pound person should consume approximately 150 grams of protein per day.
It also is important to realize that, by itself, protein has no effect on muscular gains. Contrary to claims made by various supplement manufacturers, protein powders aren’t magic formulas for building muscle. You can’t expect to simply consume a protein drink, sit back, and watch your muscles grow. This might make good ad copy, but it doesn’t translate into reality. Only through intense strength training can protein be utilized for muscular repair and promote the development of lean muscle tissue.