Multiple-transportable carbohydrates
Glucose+fructose at 2.4 g/min reaches ~1.75 g/min exogenous oxidation vs ~1.06 g/min for glucose alone
Participants
n=8 trained male cyclists (VO2max 68±1 ml/kg/min)
Protocol
Three trials, 150 min cycling at 50% of maximal power output (60±1% VO2max), each drinking one of: water (WAT); glucose 1.2 g/min (GLU); glucose 1.2 g/min + fructose 1.2 g/min (GLU+FRUC, 1:1, total 2.4 g/min)
Key Findings
Peak exogenous CHO oxidation: 1.75 (SE 0.11) g/min with GLU+FRUC vs 1.06 (SE 0.05) g/min with GLU (P<0.01)
Last 90 min of exercise: exogenous oxidation ~50% higher with GLU+FRUC (1.49 vs 0.99 g/min, P<0.05)
Background cited in the abstract (the same lab's earlier study, not this one): a glucose+fructose mix at 1.8 g/min peaked at ~1.3 g/min, ~55% above an isocaloric glucose drink
Inference, not tested here: glucose and fructose use different intestinal transporters (SGLT1 vs GLUT5), which is the usual explanation for why the blend exceeds the glucose-only ceiling
Practical Application
In 8 trained male cyclists riding 150 min at ~60% VO2max, drinking 2.4 g/min of a 1:1 glucose+fructose mix gave peak exogenous carbohydrate oxidation of ~1.75 g/min vs ~1.06 g/min from 1.2 g/min glucose alone (~50% higher over the last 90 min) — so for long rides where high carbohydrate intake is the goal, a glucose+fructose blend rather than glucose alone lets more of what is drunk be burned.
The 2.4 g/min intake here is a laboratory dose chosen to test the oxidation ceiling, not a recommended race intake; GI tolerance and performance were not reported in the abstract.
Not from this paper: intake by duration (~90 g/h for >2.5 h) is REF-066; the 1:0.8 glucose:fructose ratio and the 90-120 g/h range for adapted athletes are SYNTH-02; high intakes need gut training (REF-008).
Limitations
Small sample (n=8), trained male cyclists only
Laboratory protocol (steady intensity) — a real race is more variable
Oxidation only; no performance outcome and no GI data in the abstract
Individual fructose tolerance varies (malabsorption in some people)
How this entry was checked and changed
Why this level
regraded 2026-09-26 from A: crossover, n=8
Content correction 2026-09-27
Peak exogenous oxidation "~1.3 g/min" -> 1.75 g/min (GLU+FRUC) vs 1.06 g/min (GLU); ~1.3 g/min was the lab's earlier 1.8 g/min study.
"Ratio ~1:0.8 allows 90-120 g/h" removed from the findings: not from this paper (tested mix was 1:1 at 2.4 g/min); now under "Not from this paper" pointing to SYNTH-02/REF-066.
Year 2004 -> 2005 (Crossref); Sport cycling, running -> cycling; SGLT1/GLUT5 mechanism labelled as inference.