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Study note

The effects of medium-chain triacylglycerol and carbohydrate ingestion on ultra-endurance exercise performance.

PMID 15902986 (2005): carbohydrate, carb — Time to exhaustion, Time-trial performance, Fat oxidation (study note for endurance athletes).

Updated Jul 22, 2026

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Study note • PMID 15902986

The effects of medium-chain triacylglycerol and carbohydrate ingestion on ultra-endurance exercise performance.

International journal of sport nutrition and exercise metabolism2005 • DOI 10.1123/ijsnem.15.1.15

How to use this page

This note summarizes one study record. Check the participants, methods, results, and limitations before applying it to training.

  • Design signal: randomized trial.
  • Population relevance: athlete/trained context.
  • Consistency: single-study evidence.
  • Practical recommendation depends on tolerance, context, and whether it protects training consistency.

ELI5

In plain language

The aims of the study were to determine if medium-chain triacylglycerol (MCT), ingested in combination with carbohydrate (CHO), would alter substrate metabolism and improve simulated competitive ultra-endurance cycling performance. (randomized trial; trained cyclists).

The abstract doesn’t indicate a clear change in Time-trial performance under the tested conditions. Treat this as a signal, not a guarantee; confirm methods and context in the full paper.

Takeaways

What the abstract suggests

  • Study question: The aims of the study were to determine if medium-chain triacylglycerol (MCT), ingested in combination with carbohydrate (CHO), would alter substrate metabolism and improve simulated competitive ultra-endurance cycling performance.
  • The abstract doesn’t indicate a clear change in Time-trial performance under the tested conditions.
  • Population: trained cyclists.
  • Protocol cues (title/abstract): 270 min • 60 min • 20 min • 30 min.

Protocol

Protocol (as reported)

  • Intervention/exposure: carbohydrate, carb (vs comparison group).
  • Dose/time/duration cues in abstract/title: 270 min • 60 min • 20 min • 30 min.
  • Outcomes: Time to exhaustion, Time-trial performance, Fat oxidation.
  • Replication note: abstracts often omit adherence and timing; confirm details before changing training or supplementation.

Fit

Who it may help, and who should be cautious

Who it helps

  • Athletes similar to the study population (trained cyclists) working on fueling.
  • Athletes who can measure Time to exhaustion, Time-trial performance, Fat oxidation with a repeatable workout or time-trial effort.

Who should be cautious

  • If you have symptoms or conditions that make the intervention risky, get professional guidance.
  • If you’re near race day and can’t safely test, defer the experiment.

Methods

What the study actually did

  • Design: randomized trial.
  • Population: trained cyclists.
  • Comparator: comparison group.
  • Outcomes measured: Time to exhaustion, Time-trial performance, Fat oxidation.
  • Protocol cues mentioned: 270 min • 60 min • 20 min • 30 min.
  • Source: PubMed PMID 15902986 (2005) — International journal of sport nutrition and exercise metabolism.

Results excerpt

What the abstract reports

There was no difference in VO2 or RER between the MCT and CHO trials (P = 0.40).

Note: excerpts are short; for full context, read the paper.

Limits

Limitations and bias

  • Abstract-only summaries can miss critical details (population, protocol, adherence, and context).
  • Single studies often don’t generalize to your event, history, and training load; treat results as a starting point.
  • If your context differs (elite vs recreational; cycling vs running), adjust expectations and be conservative.
  • This is performance information, not medical advice.

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