Study note • PMID 11429627
Effect of caffeine co-ingested with carbohydrate or fat on metabolism and performance in endurance-trained men.
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
We examined the effect of caffeine co-ingested with either carbohydrate or fat on metabolism and performance in eight endurance-trained subjects who performed a random order of four experimental trials… (randomized trial; trained participants).
Effects on Time-trial performance, Fat oxidation are mixed or unclear from the abstract alone. Treat this as a signal, not a guarantee; confirm methods and context in the full paper.
Takeaways
What the abstract suggests
- • Study question: We examined the effect of caffeine co-ingested with either carbohydrate or fat on metabolism and performance in eight endurance-trained subjects who performed a random order of four experimental trials…
- • Effects on Time-trial performance, Fat oxidation are mixed or unclear from the abstract alone.
- • Population: trained participants.
- • Protocol cues (title/abstract): 6 mg • 120 min • 1 min.
Protocol
Protocol (as reported)
- • Intervention/exposure: carbohydrate, carb (vs comparison group).
- • Dose/time/duration cues in abstract/title: 6 mg • 120 min • 1 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 participants) 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 participants.
- • Comparator: comparison group.
- • Outcomes measured: Time to exhaustion, Time-trial performance, Fat oxidation.
- • Protocol cues mentioned: 6 mg • 120 min • 1 min.
- • Source: PubMed PMID 11429627 (2001) — Experimental physiology.
Results excerpt
What the abstract reports
“FAT, 196 +/- 48 and FAT + CAF, 191 +/- 55; P < 0.05, values are means +/- S.D.) and the rate of fat oxidation lower (micromol kg-1 min-1: CHO, 19 +/- 8 and CHO + CAF, 22 +/- 7 vs.”
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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