The Game Changers, a movie promoting the benefits of a plant-based diet on athlete performance has been gaining a lot of traction. With big sports stars involved like Lewis Hamilton, Novak Djokovic, Arnold Schwarzenegger, Jackie Chan and backed by Hollywood heavy weight director and producer James Cameron one can see why. However, for the uninitiated majority of those involved with this production including the chief science advisor are supporters of plant-based diets, leading to a somewhat biased slant. Therefore, the question needs to be asked “what does the research really say about plant-based diets and athletic performance”.

“love to put Viagra out of business, just by spreading the word on plant-based eating.”

James Cameron – The Independent 25/04/2018

Diets for athletic performance are extremely individualised and are geared towards the specific demands of the athlete and sport the individual competes in. In a very simplistic manner, it requires a balance of protein, carbohydrates and fats to aid with the development of lean muscle mass, energy production and recovery matched against energy expenditure or calories burned throughout the day.

Gluten Free Diets

Athletes are always looking to find that extra edge over their competitors and diet is one area that can be utilized to good effect however, all that glitters may not actually be gold. A few years ago with the explosion of gluten and wheat intolerances and celiac disease a few athletes decided to go gluten free and claimed it was responsible for improving their athletic performance, even though they hadn’t been diagnosed as celiac. Interestingly though these claims aren’t currently supported by the research, with a study in 2015 that took 13 competitive endurance cyclists with no history of celiac disease and compared their time trial performance while on a short term gluten containing diet and on a gluten free diet. The study showed athletic performance didn’t improve for the athletes on a gluten free diet with no history of celiac disease. Given, this study had a small sample size of 13 athletes and was conducted over a short time period (7-day diets) it is however currently the only study comparing gluten free and gluten containing diets on athletic performance in non-celiacs.

Ketogenic Diets

Ketogenic diets have been another diet trend amongst athletes, especially in the world of sports like CrossFit. Ketogenic diets are low in carbohydrates and high in fats, which at first glance seems counterproductive to athletic performance when carbohydrates are an athlete’s main source of energy. In the non athletic population Ketogenic diets or low carbohydrate diets have been shown to be beneficial with weight-loss and reductions in the risk of diabetes. One could argue that reducing body mass might be an important goal in endurance and weight based sports however, the current limited literature looking at ketogenic diets and athletic performance does not support the use of ketogenic diets for athletic performance. Although ketogenic diets do not negatively impact performance, they may lead to unwanted decreases in lean body mass or a drop off in skeletal muscle hypertrophy.

Plant-Based Diets

As it is becoming quickly evident the current literature investigating diet and athletic performance is sparse and generally low in quality. This trend continues when comparing plant-based diets versus omnivore (animal and plant) diets and athletic performance, especially in the elite athletic population which is the premise of The Game Changers documentary. A search of PubMed found only one review paper which systematically reviewed the current literature comparing vegetarian and omnivore diets with physical performance. The paper included 8 studies, 7 randomised controlled trials and 1 cross-sectional study and found there were no differences in athletic performance between a vegetarian-based diet and omnivore diet.

“As someone who follows a plant-based diet, I believe we need a healthier high street option that tastes amazing but also offers something exciting to those who want to be meat-free every now and again.”

Lewis Hamilton on his Neat Burger company – The Sun 29/08/2019

With such limited and low-quality evidence currently available comparing diets and athletic performance, it is extremely important in this commercial and marketing driven age that we step back and ask questions to understand where the truth lies, rather than letting a documentary “inform” us. Plant-based diets and reducing animal meat intake has been associated with health benefits, with a large section of the research on plant-based diets focusing on its potential risk reduction in chronic preventable diseases such as cardiovascular disease. At present there is limited research available analysing its effects on athletic performance with no known larger scale multi-arm studies comparing a variety of diets on athletic performance. Currently the evidence does not show a positive association between a plant-based diet and athletic performance compared to other animal meat with plant based diets.

Diets for athletes, especially elite athletes are extremely individualised and what works for one athlete might not necessarily work for another. Whatever diet is chosen, plant-based or omnivore it should be driven by a nutritionist, dietitian or health professional with sports nutrition training and be grounded in the best evidence available.  

Achilles Tendinopathies

Achilles tendon pain is a prevalent condition that is an extremely frustrating and challenging condition to treat for both patient and practitioner. Fortunately there is a strong and ever growing body of evidence that supports the use of heavy tendon load exercises in the treatment of tendinopathies, especially achilles tendinopathies (AT).

In September I published an article in the Chiropractic Australia, COCA News magazine examining AT and what the evidence currently tells us.

Taming Achilles Tendinopathies

Fluid or hydration status is extremely important in endurance sports like the marathon, getting it wrong can have disastrous consequences. As such hydration is a balancing act, not taking in enough fluids will result in dehydration and taking in too much fluid will result in Exercise-Associated Hyponatremia (EAH). EAH can be a life-threatening scenario where an athlete or individual takes on more fluid than they are losing, causing a dilution and subsequent reduction in sodium levels within the body resulting in fatigue, nausea, vomiting, dizziness and alterations in consciousness.

How Fluid Should Be Replaced

It is uniformly agreed that fluid replacement during exercise is important to prevent excess fluid loss (dehydration) and to avoid body weight loss of >2% and excessive changes in electrolyte balance which can compromise performance. How that fluid is replaced during exercise is currently of great debate with researchers unable to come to a consensus on which approach is best, drinking to a plan of 600-800ml per hour, drinking to thirst (using the sensation of thirst to determine when to drink) or drinking ad libitum (drinking whenever and in whatever volume). In light of this lack of consensus it would seem reasonable that any rehydration strategy should be flexible taking into consideration the duration of the event, the outside temperature, the effort required, sweat rate, the terrain and gradient etc. It should use thirst as a guide while not straying too far from an intake of 600-800ml per hour, but essentially not drinking more than is being lost through sweat.

Sweat Rates

Sweat rates are highly variable between individuals with an average sweat rate of approximately 1.35L/hr. There are calculators available that can help determine ones specific sweat rate. Alternatively, a simple way to establish a rough sweat rate is to weigh one’s self prior to and immediately after a 60 minute workout. The weight loss during that period divided by the time (60mins) will provide a rough sweat rate estimate – it is important to be well hydrated before undertaking the workout. The benefit of establishing an individual sweat rate estimate is it aids in understanding how much fluid is lost to sweat per hour of exercise and therefore roughly how much fluid will need to be replaced per hour.

What To Drink

Armed with a sweat rate estimate and a rehydration strategy of drinking to thirst while making sure one isn’t straying too far from the amount of fluid needing to be replaced due to sweat loss, gives you 2 of 3 key components to a solid hydration strategy. The final component is the fluid type that should to be taken in; water, hypertonic (Gatorade), hypotonic (Mizone) or isotonic (Powerade) drinks. In endurance sports the simple answer to this question is all, it is important to use a mixture of water and drinks that contain electrolytes as well as carbohydrates. Lastly, it is important to try different products and combinations during training to see what works best and to also get used to drinking while training, so when it comes to race day it is one less thing you have to think about.

Supplements Are Big Business!

Sports nutrition supplements, more formally known as nutritional erogogenic aids are part of a supplement industry that is currently booming, with sales in Australia skyrocketing to $1billion dollars per year. It is not hard to miss manufacturers bold advertising campaigns, their lists of powders, pills and liquids for pre workout right through to post workout and recovery, all there to help you “train harder” and achieve “mass gains”. If you do miss the advertising, you cannot miss the plethora of blogs and websites dedicated to sharing what the “best” performance supplements to take are.

Do Supplements Really Work?

But do these advertised supplements actually work? The simple answer is well summed up by Professor Ron Maughan who said “if it works, it is probably banned (by WADA). If it is not banned, it probably doesn’t work.” However, there are some exceptions that we will get to. For elite athletes subjected to drug testing, ergogenic supplements can be a challenging area. Studies show high rates of contamination among supplements with one study ranging from 12-58%, predominantly for prohormones and stimulants. There are also everyday health considerations for non athletes, do you want to be ingesting a supplement containing a banned substances?

How To Protect Yourself From Banned Supplements

Thankfully there are some tools out there to help athletes and individuals to navigate through the challenging world of ergogenic supplements. There are fantastic sites like informed-choice who independently test batches of supplements to determine if they contain banned substances. The Australian Institute of Sport (AIS) also have a sports supplement framework which is based around the best available evidence to determine the safety, efficacy and legality of different supplements.

Which Supplements Work And Which Are Banned?

Using the AIS framework it becomes clear which supplements have strong evidence to support their use and which don’t. Grade A supplements backed by strong evidence which aren’t banned include:

  • Caffeine
  • Beta-alanine
  • Bicarbonate
  • Beetroot juice (nitrates)
  • Creatine
  • Glycerol

Grade B supplements, those containing emerging evidence or deserve further research include:

  • Carnitine
  • Fish oil
  • Curcumin
  • Branched Chain Amino Acids (BCAA)
  • Tyrosine
  • Vitamin C and E

Grade D supplements, those that are on the banned WADA list include:

  • DMAA (stimulant)
  • DMBA (stimulant)
  • DHEA (prohormone/hormone booster)
  • Maca root powder (prohormone/hormone booster)
  • “Peptides”

Don’t be drawn in by the bold advertising nor the websites and forums. Have a thorough understanding of the risks and benefits of any supplements being considered. Consult an appropriately trained health professional to see if you actually need to be taking any supplements at all, it maybe a change in diet and training is all that is required. There are ergogenic supplements out there that have good evidence to support there ability to enhance performance in endurance, sprint and power sports. However, there are also a great deal of supplements out there that have no evidence to support there use and may well even include banned substances, so make sure you know what you are putting into your body.

We know that physical activity helps to mitigate the risks of developing preventable diseases like cardiovascular disease, obesity, diabetes etc associated with a sedentary lifestyle and physical inactivity. It is also known that exercise helps to improve memory and cognition.

A recent small scale study showed that by engaging in regular exercise at work people are more engaged, less tired, more motivated and have greater energy. So make physical activity a regular part of your lunch time break.

Exercising at work to boost your productivity.

This is a very promising small scale study looking at the effects of caffeine on tolerance to high intensity workload. The study shows that those who took 5mg of caffeine per kg were able to train at a high intensity level for 30% longer than those who didn’t take caffeine. The caffeine group also burned 40% more calories.

This suggests caffeine maybe beneficial in enabling people to maintain their “peak exercise cardiorespiratory and muscular functions for a longer duration and do so while achieving a greater energy expenditure. This opens the possibility to combine high-intensity exercise and caffeine in exercise training programs designed with the intent to maximize the exercise-induced health benefits and athletic performance.”

Does Caffeine Enhance Tolerance to High-Intensity Exercise?