As a teenager the advice I got when it came to diet and exercise was often problematic to say the least. We lifted too heavy, with terrible form and took far too little rest. This, we were told, would make us better rugby players or something to that effect. When it came to diet, we were told to ‘carb load’ before big games or tournaments to make sure we had that competitive edge. For those of you experienced in such matters, you can probably guess what happened when a team full of 18 year olds were told to load up on carbs. Yep… we had big bowls of pasta, copious amounts of sandwiches and even potato waffles just to be safe. 18 year old me wasn’t complaining but it seemed like an odd concept even at the time.
Fast forward to today and I’ve played around with every diet imaginable from fruit fasting to keto. One area that has always perplexed me though is ‘carbohydrate loading’ before a big event. Nowadays my friends who run marathons continue to swear by it while those in the lifting community advise low to moderate carbs around workout times. Nutrition will always be a contested arena and to that end, today’s post explores the birth of carbohydrate loading as a scientific concept in 1967 and examine its remarkable rise in popularity soon after.
The first truly scientific studies to emerge on carbohydrate loading for athletes came in 1967 when the Swedish research Gunvar Ahlborg and his lab partners began to experiment with different dietary protocols. Beginning on the basis that carbohydrate storage in the body was finite, and could therefore be depleted, the team set out to discover whether or not the body’s carbohydrate tolerance could be over loaded right before an event.
The reason for this was, to their minds, simple. Carbohydrates are the body’s primary fuel source (yes Keto devotees, I’m well aware ketones can be used…). So more carbs, more fuel. Easy right? Not exactly.
To overload the body’s storage of carbs, which to return to biology 101 are held in the muscles and in the liver, Ahlborg and his team had their participants run a three day low carbohydrate diet combined with an intense training regimen. The purpose of such draconian measures was to ensure that by the third day, the body’s glycogen storage had been well and truly depleted. Incidentally if anyone has run Dan Duchaine’s Bodyopus diet in the past, you’ll understand how truly draining glycogen depletion can be.
With the body now starved of glycogen and craving carbohydrates, participants were given three days of carbohydrate loading to culminate on the day of their competition.
The results? First, few participants talked to Ahlborg because his training programme was far, far too much. More seriously, the athletes, all of whom took part in a marathon after the third day of carb loading, found they had greater energy than before. Simply put, the protocol helped them run longer.
The results from Ahlborg’s team were soon replicated by others. First by his fellow Scandinavian scientists and then by his international peers. Soon it trickled into popular culture. As jogging became increasingly popular, especially in the United States, more people took to the streets to run. This meant more potential marathon runners, which meant more potential carb-loaders. The increasing acceptance of marathons as an acceptable sport was combined with a new fear of fat. Carbohydrates were being promoted by the wider society at the same time that sport scientists linked increased carb consumption to better athletic performance. It seemed a match made in heaven.
A Change of Pace
First, I will not apologise for the pun in the subheading. Second, it is clear that while Ahlborg’s carbohydrate protocol had taken the running world by storm, many were still weary of following it wholeheartedly. This was certainly the case for Dr. Dave Costill from Ball State University in Australia. In the late 1970s, Costill and his team discovered that the very nature of a marathon runner’s training depleted muscle glycogen.
Unlike Ahlborg, who believed a low carbohydrate diet was needed to deplete muscle glycogen and, in doing so, prime the body for a hearty dose of carbs right before races, Costill and his team advocated a much more moderate approach. Instead, runners were advised to do a mid to long distance run some days before the race to deplete their muscle glycogen. In the days just prior to the race, they would decrease their training volume and increase their food intake, specifically they would take more carbs.
Dr. Dave Costill had discovered in his Ball State University lab that a marathoner’s regular training adequately depleted muscle glycogen so that a simple reduction in training, accompanied by an increase in the proportion of carbohydrates in one’s diet, would create similar super-compensation. Thus, the accepted method became an early-to-mid-week depletion run of 8 to 10 miles, followed by less running and more eating. As Jonathan Beverly noted in Runner’s World in 2010, Costill’s advice was understood as less running, more eating!
Costill and his team’s research first came to light through an article Costill published in Runner’s World in 1978. Soon after it began to compete with Ahlborg’s for supremacy among the racing elite. This situation would last really until the early 2000s, when two other forms of dietary manipulation emerged.
The Western Method
Australia plays a remarkably important role in the evolution of these protocols. In 2002, Timothy Fairchild’s lab at The University of Western Australia advanced an entirely new method of carb loading. If racers took a short, fast interval run on the morning of their race, and immediately started carb loading afterwards that they would mimic the carb loading effects of those practising week long protocols. In other words, you could carb load in a single day. There was no need for advanced or arduous experiments when it could be done in one 24 hour period.
The ‘Western Method’ as this approach became known marked the last great change in carb loading practices. Anecdotally the ‘Western Method‘ is rarely discussed among my race loving friends who prefer to carb load over several days. As time goes on I suspect this is more of a lifestyle choice than anything else.
Incidentally the Western Method arrived around the same time that Stu Mittleman began popularising low-carb and ketogenic diets for long distance runners. His book, ‘Slow Burn‘ marked a turning away from the carb loading practices discussed above. It served to show that diets are a contentious business no matter what the field! Since the early 2000s, runners have appeared to take a more holistic approach, catered on the individual. That being said, the idea of carb loading still holds a certain societal appeal for many… I wonder why?
Carb Loading: A Perspective
When discussing this post with a friend of mine, he rightly pointed out that bodybuilders has been manipulating their carb intake for decades. What, he wanted to know, was so special about marathon runners? Initially I struggled to answer. Having written the post now, the answer is thankfully clearer.
Though carb manipulation is not a new phenomenon, the studies discussed in this post marked a new turn in sport science. For one of the first times in sport individuals had clinical evidence on the best dietary approach. This, countless runners imagined, would give them an edge over competitors and help push them over the finish line. Whether or not this was the case is debatable. What is not debatable is that the fine research discussed here allowed teenage Conor to justify slamming peanut butter and jelly sandwiches before rugby games. Science truly is a beautiful thing.
As always..Happy Lifting!