120 g/h Carbohydrate for Elite Marathon Fuelling: Metabolic Advantage and GI Distress

🔗 Read the full study

This scientific study evaluated the effects of different carbohydrate (CHO) ingestion rates on elite male marathon runners during simulated running.

• The study compared the metabolic effects of consuming 60, 90, and 120 grams of CHO per hour, using stable isotope tracers to measure exogenous CHO oxidation and whole-body substrate metabolism.
• Researchers found that the highest rate of 120 g·h⁻¹ resulted in significantly greater whole-body and exogenous CHO oxidation and a lower oxygen cost of running, suggesting a metabolic advantage.
• However, the study also reported that the incidence and severity of gastrointestinal symptoms, particularly nausea, stomach fullness, and cramps, were highest in the 120 g·h⁻¹ trial. The conclusion is that while high CHO doses offer metabolic benefits, strategies to improve gastrointestinal tolerance are necessary for practical application.

🔗 Link to the paper

​¹³C labelled glucose-fructose show greater exogenous and whole-body CHO oxidation1and lower O₂ cost of running at 120 vs 60 & 90 g·h⁻¹ in elite male marathoners