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

By Christopher Tack | Clinical Specialist Physiotherapist 

Nutritional supplementation has become more and more popular, but there are a fair few protein myths that come with such popularity. It’s 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 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 regarding 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

There have been vast amounts of peer reviewed scientific studies on the effects of protein shakes. When scientific studies that aim to prove or negate the benefits of any substance (medicine, supplement, etc.) are peer reviewed, this means that they’re scrutinised by other experts in the field to maintain quality standards and prevent any misinformation.

If there’s bias in a study, this would usually be identified and highlighted even before the study gets accepted to commence.

This is particularly the case of research into protein, as there are many experts in the field. For example, at the University of McMaster in Ontario, Dr. Stuart Phillips, professor of kinesiology and adjunct professor of medicine, runs the Protein Metabolism Research Laboratory. He’s also 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 the factors that help maintain, increase and decrease skeletal muscle mass. You’ll often see Dr. Phillips’ name cited and linked with hundreds of papers investigating the impact of nutrition and human muscle.

In order to prove or negate the benefit of protein supplements, researchers often compare them to an alternate substance to counteract the ‘placebo effect’. For the participants who receive the placebo instead of the substance that’s being tested, researchers regularly use a carbohydrate (such as maltodextrin or dextrose), which contains almost exactly the same amount of calories per gram as the protein. Remember that 1g of protein and 1g of carbohydrates both have 4 calories. 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 likely to be 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 efficacy of soy protein (versus whey and casein) on increasing muscle-protein synthesis (5).

Myth debunked.

Myth #2 | Protein powders are full of steroids

It’s true that large-scale studies have examined the contents of a myriad of nutritional supplements and have found unwanted ingredients added to the blend. Across 13 different countries supplements have been seen to include various substances, which include stimulants such as ephedrines and caffeine (6).

people drinking 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).

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 provides 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.

They 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).

While there is a risk of purchasing contaminated products when shopping online 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 debunked.

Myth #3 | Protein will weaken my bones

Another myth is that a high-protein diet increases risk of bone density problems and the development of bone fragility diseases.

This 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 that 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 – 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).

Protein supplements often 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).

Myth debunked.

Myth #4 | Protein-induced ketosis will kill me?

This is a rather dramatic statement. However, there are schools of thought suggesting that diets high in protein that are simultaneously low in carbohydrates, can predispose individuals to metabolic ketosis.

Metabolic ketosis is a physical state where carbohydrate stores are limited, and the body becomes more dependent upon ketone bodies in the blood (acetoacetate, beta-hydroxybutyrate, and acetone) for the primary source of energy. In fact, the Ketogenic Diet was originally developed to treat epilepsy (21).

During periods of fasting, low-carb consumption or prolonged intense exercise, the liver releases greater amounts of ketones that are utilised for energy in the absence of glycogen stores (carbohydrate stores) (22). Periods of starvation and alcoholism increase the risk of developing ketoacidosis, which is where the body can no longer control ketone production, and can lead to coma or death. This is generally irrelevant for normal, healthy individuals.

A multi-site clinical trial (23) examined the effect of low-carbohydrate, high-protein diets and did report a significant elevation of circulating ketones in the first three 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 diet.

Carbohydrates are a good energy source, however, and care should be taken to ensure each workout is fuelled appropriately.

Myth debunked.

Myth #5 | 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, for example, from meat or fish. This leads people to believe that blood lipid levels and subsequent physiological characteristics (e.g. blood pressure) will be negatively affected.

Such characteristics are risk factors for the development of cardiovascular disease, however, 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 decrease.

The benefits of high protein intake have actually been shown to 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 amount 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 debunked.

Myth #6 | Protein supplements are not as good as real food

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, or a variety of plant-based protein sources for vegans and vegetarians, should be components of a balanced and nutritionally optimal diet for those who exercise. These sources provide the essential amino acids required to boost muscle-protein synthesis and counteract degradation (32-34).


However, whole foods are not always the most efficient or easy way to get a dose of high-quality protein. Often people may refrain from consuming protein, simply because they do not want to either cook or eat whole foods. Sometimes people want a quick and simple solution to boost their protein intake post-workout, and a supplement shake best fits the bill.

Whole food sources also come with additional nutritients in the form of fats and carbohydrates. Therefore, when balancing a strict diet, ensuring the correct amount of protein (without elevating fat and carbohydrate intake), people will often require an increased protein intake without the worry of extra carbohydrates, fat and calories. People also sometimes want to increase their intake of BCAAs (branched-chain amino acids) and EAAs (essential amino acids), without adding extra fat, calories and carbohydrates.

Whole food sources of protein should be the predominant means of protein consumption (35). However, supplementation has a worthwhile place for individuals that are looking to increase their protein intake.

Myth debunked.

Take Home Message

There are a number of myths about protein consumption which are shared in the public media. However, few high-quality studies support many of the arguments made against high-protein diets.

The myths regarding high-protein diets damaging the liver, heart and kidneys of healthy individuals are unsubstantiated. Protein supplementation is considered effective and safe.

Our articles should be used for informational and educational purposes only and are not intended to be taken as medical advice. If you’re concerned, consult a health professional before taking dietary supplements or introducing any major changes to your diet.

Lauren Dawes

Lauren Dawes

Writer and expert

Lauren is an English Literature graduate originally from the South. She’s always loved swimming, has discovered the power of weight training over the past few years, and has lots of room for improvement in her weekly hot yoga class. On the weekends she’s usually cooking or eating some kind of brunch, and she enjoys trying out new recipes with her housemates – especially since shaking off student habits, like mainly surviving off pasta. Above all, she’s a firm believer in keeping a balance between the gym and gin. Find out more about Lauren’s experience here: