Endurance training on low-carbohydrate and grain-based diets: a case study

Area of Science:

• Sports Nutrition
• Human Physiology
• Exercise Metabolism

Background:

• Dietary strategies significantly impact athletic performance and physiological markers.
• Understanding the effects of different macronutrient distributions, such as low-carbohydrate (LC) versus grain-based (GB) diets, is crucial for optimizing training and competition outcomes in endurance athletes.

Purpose of the Study:

• To investigate the comparative effects of LC and GB diets on body composition, metabolic biomarkers, training consistency, and performance in an elite triathlete.

Main Methods:

• An elite triathlete underwent two 14-day dietary interventions (LC and GB) while adhering to a structured training regimen.
• Measurements included body composition, resting energy expenditure, plasma/serum biomarkers, and a maximal performance cycling test before and after each diet.

Main Results:

• The LC diet led to greater training disruptions and negative subjective experiences compared to the GB diet.
• Elevated total cholesterol, HDL cholesterol, LDL cholesterol, perceived exertion, and heart rate were observed on the LC diet.
• The LC diet resulted in the lowest levels of blood insulin, resting lactate, postexercise lactate, and C-reactive protein.

Conclusions:

• The LC diet presented a mixed outcome, with both beneficial and detrimental effects observed.
• A significant finding was the disruption to the athlete's scheduled training under the LC diet.
• The potential influence of training disruptions on pretest-posttest study designs warrants consideration by researchers.