The 90g/hour multiple-transportable-carbohydrate guideline is grounded in gut-transporter physiology, not just a trend-following round number
Interpretation
Wallis et al.'s foundational 2005 trial showed combining maltodextrin with fructose at a 2:1 ratio raised carbohydrate oxidation by ~40% over maltodextrin alone, because glucose and fructose are absorbed via separate intestinal transporters — this mechanism, not marketing, is the basis for the ~90g/hour 'multiple transportable carbohydrate' guideline now common in high-carb fueling advice.
Practical implication
When explaining the 90-120g/hour fueling trend, lead with the glucose/fructose dual-transporter mechanism rather than presenting it as an arbitrary or purely trend-driven number.
Sources
1 source, independently verified.
MSSE 37(3):426-432. Combining maltodextrin with fructose at a 2:1 ratio raised carbohydrate oxidation rates by ~40% versus maltodextrin alone, allowing up to ~90g/hour of carbohydrate to be absorbed — the physiological mechanism (separate glucose/fructose gut transporters) underlying the 90g/hour multiple-transportable-carbohydrate guideline.