Protein Shakes | Are They Good Or Bad For You? | 8 Myths Debunked


By Christopher Tack |

Clinical Specialist Physiotherapist

You’ve all heard the protein myths.

The popularity of nutritional supplementation has become more and more apparent in the world we live in. It is not uncommon to see high-level celebrities and sports people putting their names and faces to branded protein shakes and snacks, which is an amazing evolution of our culture as more people want to get and stay in shape.

Protein supplementation is one of, if not the biggest and most commonly bought and consumed forms of workout nutrition (1-2). However, along with this rise in popularity comes the spread of unsubstantiated fact and disinformation as to the perils and dangers of taking these products.

Here we aim to breakdown some of these myths and help you answer the question-  are protein shakes good for me, or bad for me?

Myth #1 | Protein shakes are a placebo


Scientific studies, such as randomised controlled trials, take no prisoners. Peer review of research articles which aim to prove or negate the benefits of any substance (medicine, supplement, etc.) also gives no quarter.


If there is bias in an experimental it is usually the case that this would be found and highlighted even before the study gets accepted to be commenced.


This is particularly the case of research into protein as there are a number of very intelligent and respected scientists in the forefront of these experiments. For example, at the University of McMaster in Ontario, Canada; Dr. Stuart Phillips runs the Protein Metabolism Research Laboratory. He is both a Professor of Kinesiology and an adjunct Professor of medicine. He is a fellow of the American College of Sports Medicine and the American College of Nutrition.

The central focus of this research facility is to investigate what factors assist to maintain, increase and decrease skeletal muscle mass. As such you will often see Dr. Phillips’ name cited and linked with literally hundreds of papers investigating the impact of nutrition and human muscle.

Needless to say, Dr. Phillips and his colleagues (such as Rob Morton) are intelligent folks who are able to ascertain whether a specific nutritional intervention is able to influence synthesis of protein tissue in muscle.


In order to prove or negate the benefit of protein supplements, they have to compare them to an alternate substance to counteract the placebo effect. For this, researchers use a carbohydrate (such as maltodextrin or dextrose) which ensures that the alternate substance has the same amount of calories per gram as protein. Remember that 1g of protein and 1g of carbohydrates both have 4 calories. So as long as the carbohydrate and protein supplements used both have the same mass, we can be assured that any change seen in protein metabolism will not be due to an increase in calories consumed, but is otherwise associated with the specific substance ingested.

Experiments have shown that whey and casein protein supplements allow greater increases in lean mass and strength compared to placebo (3).

Pea proteins have also been compared to placebo and show greater muscle gains than when a maltodextrin supplement is provided (4).
Other studies consider that the effectiveness of whey and casein proteins are so well established that a placebo is not required, and comparisons of effectiveness can be made between sources and whey and casein as a baseline. For example, comparisons have been made to evaluate the effectiveness of soy protein (versus whey and casein) on increasing muscle protein synthesis (5).


It is obvious that those in charge of the research are too intelligent, and the available evidence base is sufficient to show that protein supplement ingestion is not placebo.


Myth #2 | Protein powders are full of steroids


It is quite true that large-scale studies have examined the contents of a myriad of nutritional supplements and have found unwanted ingredients added to the mix.

Across 13 different countries supplements have been seen to include various nefarious substances, which include stimulants such as ephedrines and caffeine (6).


Cheap high calorie protein shake

Other studies have demonstrated the presence of anabolic steroids such as methandienone (a testosterone precursor) and nandrolone metabolites (7). Others have been seen to include stanozolol, boldenone, Turanibol, and oxandrolone, which are all synthetic anabolic steroids (6).

Additionally, the supply of such tainted supplements was all from 5 specific countries with nearly 19% from the UK (the same as the amount from the USA) (6).

Obviously, a lot of supplement suppliers are unscrupulous and there is certainly smoke to this particular fire. However, many suppliers are honest and respectable regarding their products. For example, Myprotein is the only nutritional supplier in Europe to have a bespoke manufacturing facility which holds an A Graded BRC accreditation. This provides a standardised level of quality and safety which ensures that throughout production the products sold can not come into contact with substances which are not found on the label!

Myprotein also goes as far as to provide an Informed-Sport Range where specific batches are rigorously tested by an independent world-class accredited anti-doping laboratory (HFL Sports Science) to ensure for athletes that their products do not contain items on the World Anti-doping Agency prohibited list.

There also open their doors for further independent testing and ranking from FDA approved laboratories by LabDoor, who rank Myprotein Impact Whey Isolate their top-ranked protein supplement, with Myprotein Impact Whey coming in third (8-9).

Obviously whilst there is a risk of purchasing contaminated products when shopping on-line or even in your local shops, especially if you’re a drug-tested athlete. This risk can be removed by researching respected and accredited suppliers before you buy.


Myth #3 | Protein will wreck my kidneys


This particular untruth is perpetuated by the unsubstantiated theory that consuming too much protein places too large a metabolic burden on the kidneys and this will lead to renal failure.

Specifically, animal model studies suggest that excessive protein intake above the recommended daily allowance will increase glomerular pressure and filtration rate of blood in the kidneys (10-11).


The truth is there is no substantive scientific evidence that high protein intakes cause kidney problems in healthy individuals who exercise. The application of animal disease models or findings from humans with concurrent kidney disease is a flaw inherent in the research (11), which reduces the generalisability of the data and prevents inferences being made to a healthy population (12).

In actual fact, when studies prospectively follow healthy folk with a high protein diet over time, there is no associated disruption to their kidney function and general health (13).

Additionally, studies comparing vegetarians (with a lower protein intake) and animal product eaters, find no statistical difference in rate or severity of future kidney disease (14) and no acute change in kidney function (15).

The current state of clinical and epidemiological evidence suggests that more research is required to investigate high protein intake in “at-risk populations” (those who already have a renal disease for example). However, this is more due to a scarcity of evidence, rather than evidence of a negative effect (16-17).

It seems that high protein intakes are not actually damaging in healthy individuals, but those with underlying renal issues should be more cautious when consuming more protein (12,17).


Myth #4 | Protein will weaken my bones


Another scary story placed at the feet of a high protein diet is the risk of bone density problems and the development of bone fragility diseases, such as osteoporosis.

This postulation is based on the theory that by consuming more protein our bones will excrete more calcium which is required to sustain bone density.


This hypothesis stems from early studies which show that the acidity of an individual’s urine is greater when consuming a diet high in protein. It is suggested that calcium is drawn from the bones to buffer the acid load (2).

However, more recent studies show that via calcium isotope trackers we can see that the predominant source of calcium in urine is not from bone resorption (bone breakdown) at all; in fact, it is from the intestines (18).

There are also arguments that the literature from which the original theory was devised is plagued with flaws (including small sample sizes and other methodological errors) and that inappropriately high doses of purified protein were used which go beyond what would be consumed via supplements (19).

Conversely, it is also nowadays apparent that protein supplements will list phosphates in their list of ingredients, and it is known that this will negate any effect on calcium release to buffer acid load (2).

The final nail in this proverbial coffin is that data also now suggests that elderly individuals at risk of bone density issues and osteoporosis should actually aim to consume more protein than the current recommended daily allowance of protein (>0.8g/ kg/ day) to optimise their bone mass (20).


Myth #5 | Protein-induced ketosis will kill me?


Ok, I agree this is a rather dramatic statement. However, there are schools of thought suggesting that diets high in protein, whilst simultaneous low in carbohydrates, can predispose individuals to metabolic ketosis.

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Metabolic ketosis is a physical state where as carbohydrate stores are limited, the body becomes more dependent upon ketone bodies in the blood (acetoacetate, beta-hydroxybutyrate, and acetone) for the primary source of the bodies energy. In fact, The Ketogenic Diet was originally developed in the 1920’s and gained more recognition following the release of the Meryl Streep film “… First Do No Harm” in the 1990’s, in which the diet is used to treat a young boy with epilepsy (21).

In essence during periods of fasting, low-carb intake or prolonged intense exercise the liver releases greater amounts of ketones which are utilised for energy in the absence of glycogen stores (22). However, the more ketones floating around in the blood, the greater the risk of developing metabolic acidosis (a condition that occurs when too much acid is accumulated, which can lead to coma or death).

Once again, however, the clinical relevance of this postulation for normal healthy individuals is in question.

A multi-site clinical trial from 2003 (23) examined the effect of low carbohydrate, high-protein diets and did report a significant elevation of circulating ketones in the first 3 months. However, after a longer period of time the participants’ urinary ketone concentrations reduced, and by 6 months none of the subjects displayed the presence of urinary ketones (2). This indicates the body’s ability to adapt and change when exposed to this dietary method.

Additionally, when aiming to sustain lean body mass and develop muscle, it is likely that a high protein diet will occur alongside sufficient carbohydrates to sustain sufficient calories to maximise muscle protein synthesis. Carbohydrates are a good energy source, and care should be taken to ensure each workout is fuelled appropriately.


Myth #6 | Too much protein will give me a heart attack


A high protein diet taken from dietary whole food sources is likely to also lead to a greater intake of fats. This fact leads people to believe that blood lipid levels and subsequent physiological characteristics (e.g. blood pressure) will be negatively affected.

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Such characteristics are obviously risk factors for the development of cardiovascular disease.

However, this premise has not been proven in any scientifically controlled studies. For example, studies have actually shown an inverse relationship between consumption of animal and vegetable proteins and the risk of cardiovascular disease (24). This means that as protein intake is increased, cardiovascular disease risk was shown to reduce.

The benefits of high protein intake actually improve various other aspects of cardiovascular function, such as decreasing lipid profiles (25) and reducing blood pressure (26).

Of course, the consumption of high-fat diets (alongside high protein intake) will increase the number of saturated fats and cholesterol consumed by individuals. However, through better awareness and nutritional education many people should be able to minimise fat intakes, and of course, many protein supplements are available that contain little to no fat.


Myth #7 | Protein could cause my liver to fail


Similarly to both renal and heart-related diseases, the American Heart Association has previously postulated that the intake of high protein diets may lead to issues with liver function as the liver is strained by the task of metabolising the protein (27).

However, similarly again there is little or no scientific evidence to support this contention.


Animal model studies from back in 1988 showed that rats were given a high protein diet display structural changes in the mitochondria found in the rats’ livers (28). However, these findings are not suggested to show the development of disease, and in fact, it was proposed that this was, in fact, a positive adaptation to the extra stress which the liver was placed under (28).

Actually, the importance of sustaining a high protein diet for those who have a liver disease is well established (2). Protein is required to both promote tissue repair but also to provide methionine and choline which help convert fats to lipoproteins to be removed from the liver (29).

It is suggested that high protein intakes can balance against the greater degrees of protein catabolism which is a byproduct of liver disease (30), and may even be helpful for those with liver dysfunction due to alcoholism (31).


Myth #8 | Protein supplements are not as good as real food


Admittedly whole food proteins from animal sources provide the highest quality of protein which we can consume.

Foods such as poultry, meat, fish, eggs and milk should be components of a balanced and nutritionally optimal diet for those who exercise. These sources provide complete proteins with a dose of the essential amino acids required to boost muscle protein synthesis and counteract degradation (32=34).

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However, there are also issues with these sources.

Firstly, not everyone eats meat or other animal products, which significantly reduces their chances of consuming a high-quality protein (unless they supplement their diet).

Secondly, food is not always the most efficient, easiest or even preferred to get a dose of high-quality proteins. Often people may refrain from consuming protein, simply because they do not want to either cook or just eat a whole food. Sometimes people want a quick and simple solution to boost protein synthesis post workout and a supplement shake best fits the bill!

Lastly, whole food sources do come with additional factors- namely the previously mentioned saturated fats and cholesterol. Therefore, when balancing a strict diet, ensuring the correct amount of protein (without elevating fat intake) people will often require their protein dose increased without the worry of extra fat and calories. People sometimes want to add BCAA (Branch Chain Amino Acids) and EAA (Essential Amino Acids), but without the kcal and fats!

I would agree with nutritional guidelines that suggest whole food sources of protein should be the predominant means of protein consumption (35). However, it is not always as cut and dried as the research may suggest and supplementation has its very worth place for individuals that are suited to the above.


Take Home Message


There are a number and variety of tall tales about protein consumption which are shared in the public media. However, little or no high-quality evidence backs up the theoretical arguments posed against high protein diets.

The myths of protein-damaging your liver, heart and kidneys are unsubstantiated. Protein is effective and safe and should be considered so when you decide upon how best to supplement your diet.

Many thanks,

Chris Tack