Development and validation of a dietary screener for carbohydrate intake in endurance athletes

BACKGROUND: Studies have shown that the majority of endurance athletes do not achieve the minimal recommended carbohydrate (CHO) intake of 6 g/kg of body weight (BW), with potentially negative impacts on recovery and performance. The purpose of this study was to develop and validate a rapid and easy to use dietary screener to identify athletes who do and do not achieve a CHO intake > 6 g/kg BW in the context of endurance sports. METHODS: The dietary screener was developed using multiple logistic regression modeling of data from a sample of 1571 non-athlete adults (826 women and 745 men, mean age 44.75 ± 14.2 years) among whom dietary intake was assessed using a validated web-based food frequency questionnaire (web-FFQ). Three models were developed based on whole food intake using the 5, 10 and 15 most significant variables predicting CHO intake. The three models were then validated in a target population of non-elite endurance athletes having taken part in multisport events (n = 175, 64 women and 111 men, mean age 37.1 ± 11.3 years) and compared using sensitivity, specificity, positive and negative predictive values (PPV and NPV, respectively) and c-statistics. RESULTS: The 15-variables model provided significantly better accuracy in predicting CHO intake adequacy in non-elite endurance athletes (c-statistic = 0.94) compared with the 10- and 5-variables model (c-statistic = 0.90 and 0.71 respectively). The 15-variables model predicts CHO intake adequacy in the target population of endurance athlete with a sensitivity of 89.5%, a specificity of 87.3% and PPV and NPV of 77.3 and 94.5%, respectively. CONCLUSION: We have successfully developed a short and valid dietary screener that identifies endurance athletes at risk of not achieving a CHO intake > 6 g/kg BW. Use of this rapid screener may help alleviate the highly prevalent issue of suboptimal CHO consumption in the endurance sports realm.