Fat in Your Diet and Running Injuries

A study published earlier this year in the Journal of the International Society of Sports Nutrition found a potential link between fat in the diet and overuse injuries in competitive female runners. Too much fat in the diet is unhealthy, but a certain amount is necessary, especially for high-energy activities like running. For active people, the recommended amount of fat in the diet is thirty percent of total calories. The authors of the study hypothesized that eating less than the recommended amount of fat meant lower energy levels in runners, and may therefore play a role in overuse running-related injuries. By the end of the study the authors concluded that injury in 64% of the subjects could be predicted based on total grams of fat consumed.

The study followed 86 competitive female runners, between the ages of 18 and 53, who each ran a minimum of 20 miles per week. The participants answered questions related to their medical history, running routines, their other activities, and any previous running injuries. They also filled out eating logs and provided details about their diets and attitudes toward food and nutrition. The height, weight, and body mass index (BMI) of each participant were recorded, and each was measured for her flexibility, oxygen capacity, and balance. Study participants were interviewed every three months, for a one-year period. They answered questions about changes in their running routines, health status, and running-related injuries. In this case, a running-related injury was defined as one to the lower back, or lower extremities, resulting from overuse.

Forty-seven subjects reported a running-related injury to the foot, ankle, knee, or hip during the study period. Stress fractures and tendonitis were the most common problems. No important differences were observed in total intake of carbohydrates, protein, fiber, or other vitamins and minerals between injured and non-injured runners, but in general injured runners consumed a lower percentage fat calories than non-injured runners. Runners consuming less than the recommended daily percentage of dietary fat were 2.5 times as likely to sustain an injury as those who consumed at least the recommended amount.

The authors maintained that this was an observational study, meaning that certain factors cannot be controlled, and therefore prevent the establishment of an absolute cause-and-effect relationship. Mean differences in fat intake between the two groups were small, but obvious. It is unlikely that inadequate fat intake alone causes injuries. More likely it plays a role in development of certain types of overuse injuries, such as stress fractures. Insufficient fat in the diet means less available energy, which can limit important functions, like tissue maintenance and repair, crucial for recovery after long workouts. Information acquired from this study can be used as a starting point for follow up studies to further investigate dietary factors that may influence injury risk, in the hope of making progress in prediction and prevention of sports-related injuries.

Gerlach, K., Burton, H., Dorn, J., Letty, J., Horvath, P.

Fat Intake and Injury in Female Runners

http://www.jissn.com/content/5/1/1