My Class Project Proposal
Marathon running, once a niche test of human endurance, has become a mainstream pursuit, with over 1.1 million participants annually in the U.S. alone. Despite its popularity, more than 40% of marathoners report “hitting the wall,” characterized by severe fatigue and diminished pace due to near-complete depletion of glycogen stores (Rapoport, 2010). This phenomenon underscores a critical knowledge gap among runners regarding carbohydrate (CHO) intake and fueling strategies. Research reveals that only 28% of endurance athletes can correctly identify current CHO-loading guidelines, while even fewer understand post-competition recovery strategies (Sampson et al., 2023). This lack of awareness perpetuates poor nutritional practices, compromising both performance and recovery.
The problem extends beyond knowledge gaps to quantifiable underconsumption of carbohydrates. 45–98% of female athletes across varying sport types fail to meet recommended CHO intake, leading to low carbohydrate availability (Lodge et al., 2023). This deficiency not only impairs athletic performance but also contributes to muscle fatigue, hypometabolism, and other physiological consequences (Lodge et al., 2023). The prevalence of low carbohydrate availability also presents a significant public health concern. Popular low-carbohydrate diets among athletes are linked to negative health outcomes, including impaired thyroid function, menstrual dysfunction, bone density loss, and chronic fatigue (McKeown et al., 2020). These consequences highlight the urgent need to improve education and awareness around proper carbohydrate intake, particularly as low-carb diets continue to gain popularity despite evidence of their harmful effects in endurance sports.
Glycogen stores are highly variable based on individual factors such as body composition, training status, and dietary intake, and there is currently no standardized equation or methodology to determine an individual’s CHO availability status. The majority of studies have simply assessed CHO intake without accounting for dynamic fluctuations in glycogen levels throughout the day or during exercise. Furthermore, no specific test exists to directly measure glycogen levels, and these levels are constantly fluctuating based on activity levels and carbohydrate intake.
To address these challenges, my study aims to develop a personalized algorithm that integrates wearable device data (e.g., heart rate and activity levels), continuous glucose monitoring (CGM), dietary logs, and body composition metrics to estimate an athlete’s current glycogen availability. This model will enable athletes to quantify real-time glycogen availability, optimize fueling strategies before, during, and after exercise, and evaluate internal training loads and recovery needs. By moving from generic fueling recommendations to actionable, personalized insights, this analysis provides a systematic approach to estimating energy demands based on personalized physiologic parameters. The proposed algorithm has the potential to revolutionize how athletes approach nutrition, offering a quantitative basis for improving health and optimizing performance.
By providing individualized recommendations, this analysis will have far-reaching implications for athletes, coaches, the sports nutrition industry, and public health. Improved carbohydrate management can enhance performance by up to 3% (Hawley et al., 1997)—a critical difference for marathoners aiming for personal bests or qualification times. It also ensures athletes are training in optimal glycogen states, preventing overtraining or underperformance. Additionally, nutrition companies can leverage these insights to create targeted marketing campaigns and product formulations, emphasizing the need for precise CHO intake during training and competition. Adequate CHO intake during exercise has also been shown to mitigate exercise-induced muscle damage, reduce internal training load, and improve recovery (Viribay et al., 2020), meaning overall healthier athletes and fewer encounters at the medical tents.
The growing interest in endurance sports offers an opportunity to disseminate evidence-based nutritional strategies to improve health outcomes across diverse populations. Knowledge is the first step toward change. By improving awareness of glycogen availability through a data-driven individualized approach and addressing the lack of understanding surrounding CHO intake could mitigate the high prevalence of low carbohydrate availability among athletes and therefore optimize health and performance.
References
Hawley, J. A., Burke, L. M., Angus, D. J., Fallon, K. E., Martin, D. T., & Febbraio, M. A. (1997). Effect of altering substrate availability on metabolism and performance during intense exercise. British Journal of Sports Medicine, 31(3), 204–212. https://doi.org/10.1136/bjsm.31.3.204
Lodge, C., Bowtell, J., & Sanders, D. (2023). Prevalence and impact of low carbohydrate availability in endurance athletes: A systematic review. International Journal of Sport Nutrition and Exercise Metabolism, 33(1), 1–15. https://doi.org/10.1123/ijsnem.2022-0090
McKeown, N. M., Sampson, L., & Ludwig, D. S. (2020). Low-carbohydrate diets: Effects on metabolic health and exercise performance. Current Opinion in Clinical Nutrition and Metabolic Care, 23(4), 296–302. https://doi.org/10.1097/MCO.0000000000000663
Rapoport, B. I. (2010). Metabolic factors limiting performance in marathon runners. PLoS Computational Biology, 6(10), e1000960. https://doi.org/10.1371/journal.pcbi.1000960
Sampson, J. A., Stellingwerff, T., & Skiba, P. F. (2023). Knowledge gaps in carbohydrate loading and recovery among endurance athletes: A survey-based study. Sports Medicine, 53(2), 345–359. https://doi.org/10.1007/s40279-022-01734-1
Viribay, A., Barranco, I., Clemente-Suárez, V. J., & Courel-Ibáñez, J. (2020). The role of carbohydrate intake in mitigating exercise-induced muscle damage and enhancing recovery: A systematic review. Nutrients, 12(12), 3859. https://doi.org/10.3390/nu12123859
