Protein Supplements: Weighing Up the Pros and Cons

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The protein supplements industry is a modern phenomenon on the rise; figures from Euromonitor show that sales of sports related nutrition products grew by 14% to reach £200 million in 2010 in the UK1, and in 2012 worldwide sales reached £4.9 billion2!

There is an abundance of protein supplement products available including: protein shakes, protein powders, protein bars, protein gels and protein capsules. When used along with exercise, protein supplements are promoted as enhancing: muscle mass, metabolic rate and physical performance. They vary in composition and can contain 100% protein, or mainly carbohydrate with some protein and fat added3.

As this is such a topical area there is a LOT of information to cover in this blog, but you can skip to “my verdict” at the end of this post for an overall summary.

Special thanks to my good friend, Sports Nutritionist Alex Larkin, for her advice when writing this blog post.

The Pros


Can Help Athletes Meet Their Increased Protein Requirements

The International Society of Sports Nutrition recommends that those who exercise should try to reach their protein requirements via whole foods, but protein supplements can be a practical way for high intensity athletes to meet their increased protein requirements quickly after a workout (per day: strength athletes require 1.4-2g/kg, endurance athletes require 1.2-1.4g/kg, the sedentary individuals require 0.8 – 1g/kg). If opting to use protein supplements, they should contain both whey and casein protein because of the “high protein digestibility, corrected amino acid score and ability to increase muscle protein [mass]”4,5.

Creatine Can Aid Physical Performance

Some protein shakes contain creatine which is a nitrogenous organic acid produced from amino acids. The European food safety authority report that there is sufficient evidence which shows that for high intensity athletes consuming 3g of creatine per day may help to achieve “an increase in physical performance during short-term, high intensity, repeated exercise bouts”6 (see related “cons” below).

May Be Useful With Exercise-Induced Poor Appetite

It has been found that some people experience exercise-induced poor appetite after high intensity exercise7, in these cases protein shakes may be better tolerated than whole food.

Some Evidence to Support the Use of Branched Chain Amino Acids

Branched chain amino acids are often found in whey protein supplements, some research indicates that these type of amino acids may improve recovery and exercise performance during intense exercise4, 8-10. However, as outlined below the overall evidence base is thought to be insufficient to prove their effectiveness (see related “cons” below).


Protein supplements are quick and easy to use, and may be useful if time, cooking facilities or cooking skills are limited. They can also be useful if you are specifically trying to increase the protein content of meals without raising the fat or calorie content too much.


Depending on the specific product, some protein supplements can be cost efficient11. For elite athletes protein supplements are often provided via sponsorship which may result in overall cost savings.

The Cons

Usually Not Necessary

The Department of Health recommends that adults should not consume more than twice the recommended daily intake of protein which is 55.5g for men and 45g for women12. The average daily protein intake in the UK is 88g for men and 64kg for women13, and as protein shakes often include roughly 20 – 40g of protein per serving, the consumption of protein shakes could easily lead to an excessive protein intake. The British Dietetic Association reports that when energy requirements are met, a balanced diet will usually provide enough protein to meet the increase in requirements associated with exercise14. As a comparison, a chicken breast contains roughly 30g of protein which is often the level of protein found in protein shakes.

Poor Supporting Evidence

The overall evidence base for the use of protein supplements isn’t very strong; the European Food Safety Authority reports that there is insufficient evidence to support a cause and effect relationship between whey protein supplements, branched chain amino acids or L-Glutamine and: the growth or maintenance of muscle mass, an increase in endurance capacity, skeletal muscle tissue repair, and faster recovery from muscle fatigue after exercise15-17.

Health Risks

It has been shown that consuming too much protein over a long time can worsen existing kidney problems and can increase the risk of developing osteoporosis18. Side effects of over the counter protein supplements include: dehydration, constipation, increased bowel movements, nausea, cramps, bloating, reduced appetite, fatigue and interaction with medication12, 19.

May Contain Illegal and Harmful Substances

An investigation by the UK Medicines and Healthcare Regulatory Agency found that 84 sports nutrition products which were being sold contained dangerous ingredients including steroids, stimulants and hormones which can result in: kidney failure, seizures or heart problems. One specific product “Celtic Dragon” was taken off the market after causing two men to be hospitalised with severe jaundice and liver damage12. The biggest risk is usually with supplements bought online, but even legal sports supplements can be contaminated by illegal substances. There have been examples of this resulting in doping scandals for professional athletes; the professional boxer Enzo Maccarinelli was suspended from boxing for 6 months after testing positive for a banned substance which was reportedly found in a fat burning supplement described as an “approved supplement for fighters”20, 21. You can check whether specific supplements have been registered as batch tested for illegal substances using websites such as

Risks Associated with Creatine

Although there have been some proven effects of creatine as outlined above, the European Food Safety Authority reports that a cause and effect relationship has not been established between the consumption of creatine and an increase in endurance capacity or performance22. Also the long term effects aren’t clear; creatine can interact certain medications and there can be side effects such as weight gain, anxiety, kidney problems, nausea and vomiting5, 23, 24. Creatine is not advised for those under 18 years old, or for pregnant or breastfeeding women21. There are also those who don’t respond to creatine supplementation at all due to their individual physiological make up, so experience no benefit from it’s use25. It is important to remember that from a moral point of view many sporting organisations don’t support the use of ergogenic aids such as creatine (ie. substances that improve exercise performance)26.

Risks Associated with Branched Chain Amino Acids

Branched chain amino acids are deemed “possibly safe” when taken orally, side effects include fatigue and reduced coordination10.

May Not Actually Contain Any Protein!

If the protein supplement hasn’t been batch tested it might not really contain ANY protein to begin with! A recent BBC documentary “Pills, Powders and Protein Shakes”found that when they tested a protein supplement called Par Nutrition which advertised a protein content of 70%, it turned out to have less than 2% protein content….which is 7 times less than flour! Non batch tested protein supplements may also have a poor protein quality and blend which can reduce the amino acid bioavailability, meaning not all of the protein listed might actually get used by the body.

Not Always Nutritionally Balanced

Protein shakes are often marketed as meal replacements, however not all of these are nutritionally balanced. As highlighted above this could lead to an excess intake of protein, but it could also lead to nutritional deficiencies, and reducing the bulk in your diet could harm your digestive system.

Unwanted Weight Gain

As some protein supplements also contain carbohydrate and fat they can have a high calorie content which can lead to weight gain if exercise levels aren’t high enough. From a quick google search I found one muscle gain product which contained 1260 kcal in one serving which is the same as four McDonald’s cheeseburgers! If you are aiming for weight loss the chief executive officer of the International Society of Sports Nutrition recommends that the protein shake should contain more than 50% protein3.

May Be a Waste of Money

There are so many different brands of protein supplements and different suitable snacks to have after the gym, but I compared the cheapest high street protein shakes I could find to a cheap post workout snack (such as value range rice cake with banana and peanut butter or whole wheat pita bread with hummus). I found that the protein shake would cost roughly 70p – £1 per serving, compared to roughly 20-30p for the whole food snack. For the equivalent protein content of roughly 30g, a chicken breast costs marginally less than a serving of a cheap protein shake.

My Verdict

Batch tested good quality protein supplements can be useful as an addition to a well-balanced diet for high intensity strength athletes aiming to meet their increased protein requirements; especially if time constraints, cooking facilities or cooking skills are an issue, but it is important to choose a reputable brand or ask your GP to refer you to a Sports Dietitian for guidance.

However most people already exceed their protein requirements and will easily meet their increased protein requirements associated with exercise using whole foods such as: red meat, poultry, eggs, dairy, beans, tofu and nuts.

Overall I feel that wholefoods are the better option to go for considering that the majority of the health claims related to protein supplements aren’t warranted and there are many possible associated health risks.



  1. Sports Nutrition in the United Kingdom. Euromonitor, April 2011.
  11. Tipton KD, Wolfe RR: Protein and amino acids for athletes. J Sports Sci 2004, 22(1):65-79.

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