On April 17, the International Association of Athletics Federations (IAAF), which is the international governing body for the sport of athletics, released a consensus statement on nutrition for athletics.
A team of 50, including the Head of Sports Nutrition at the Australian Institute of Sport and representatives from Athletics Canada and the Canadian Sport Institute, looked at new developments in sports nutrition to see how they apply to the five core areas of athletics: sprints, jumps/throws/combined events, middle distance, long distance and ultra distance/mountain running.
The consensus statement recognized the fact that sports nutrition is a constantly evolving science and so these summaries are needed to pull recent evidence together and translate it into practice. Similar studies were conducted in 1995 and 2007.
Reading through the statement, I noticed several findings that are either not well-known or were stating the opposite to commonly held sports nutrition myths.
One seemingly lesser known issue, even in elite athletics, is Relative Energy Deficiency in Sport (RED-S), formerly known as Female Athlete Triad syndrome, which can occur when an athlete consumes less calories than they're expending. The triad referred to the combination of disordered eating, loss of menstruation and osteoporosis, but can also contribute to reduced testosterone levels in men, increased risk of illness and injury, cardiovascular disease, and impaired training capacity and performance in athletes who are experiencing an ongoing calorie deficit.
New findings outlined in the statement highlighted these additional risks. The importance of an athlete consuming enough calories for their training load is emphasized for athletes across all areas of athletics. Since an ongoing calorie deficit is now considered to be a major risk factor in the development of bone stress fractures, it should be addressed in both prevention and treatment.
A couple myths that were addressed in the consensus statement centered around the inclusion of supplements and the avoidance of gluten. Athletes should take a "food first" approach to their diet and supplements should only be used to address nutrient deficiencies or to help the athlete meet nutritional goals when it may not be practical to eat food, such as taking an energy gel in the middle of a marathon. As well, contrary to the belief of many, there have been no direct benefits associated with the avoidance of gluten by clinically healthy athletes.
Other findings:
Only five supplements have a base of evidence to support claims that they contribute to athletic performance, and not all are appropriate for all disciplines.
Nutrition can aid in the rehabilitation of muscle injuries. Goals around recovery should include adjustments to energy (calorie) requirements and distribution of protein intake to minimize the loss of lean muscle mass and increase muscle repair.
Vegetarian diets can support athletic demands but special attention and planning are required to ensure adequate calorie and nutrient intake since specific nutrients are less abundant and/or less well-absorbed (e.g. iron) when coming from plant sources.
Consuming carbohydrates during exercise can provide additional benefits via the brain and nervous system. Carbohydrates can stimulate areas of the brain that control pacing and reward systems via communication with receptors in the mouth and gut. This evidence provides another reason for the intake of carbohydrates during distance events.
The consensus statement from the IAAF serves as a good round-up of current, reliable evidence and how it relates to athletes in specific disciplines. One particularly useful section of the statement includes a table with the common characteristics of different events (sprints, middle distance running, jumping events, etc.) and the key nutritional strategies to be considered for athletes who train for, and compete in those events.
One very important point to keep in mind is that these findings/recommendations are applicable to athletes involved in the field of athletics who are training on a consistent basis and whose physical demands of their sport require specific dietary considerations. These recommendations are not meant for the recreational participant.
The IAAF's consensus statement was published in the International Journal of Sport Nutrition and Exercise Metabolism but can be accessed for free at journals.humankinetics.com by searching "International Association of Athletics Federations Consensus Statement 2019: Nutrition for Athletics."
Kelsey Leckovic is a registered dietitian with Northern Health working in chronic disease management.
