# Does caffeine ingestion before a short-term sprint interval training promote body fat loss?

PMID: 31826183
Journal: Brazilian Journal of Medical and Biological Research
Published: 2019 Dec 5
Authors: Ferreira GA, Felippe LC, Bertuzzi R, Bishop DJ, Ramos IS, De-Oliveira FR, Lima-Silva AE

## Question

Does caffeine before a single SIT session increase energy expenditure, and does caffeine before 2 weeks of SIT increase body fat loss versus placebo?

## Summary

In 20 physically active men, 2 weeks of cycling sprint interval training reduced body fat only in the group taking 5 mg/kg caffeine before each session. Caffeine increased post-exercise energy expenditure after the first session and no caffeine-related side effects were reported.

## Population

- Healthy physically active men.
- Sample size: 20
- Age: 25.9 +/- 5.1 years
- Sex: Men
- Fitness level: Physically active
- Health status: Healthy normal-BMI

## Methodology

- Placebo-controlled double-blind randomized training study
- 2 weeks
- Laboratory cycling sprint interval training
- Randomized and controlled study design.

## Protocol

- Caffeine plus SIT.
- Modality: Cycling.
- Work intervals: 30 seconds all-out.
- Recovery: 15 seconds self-paced active recovery.
- Sets or repetitions: 13.
- Intensity: All-out; 5 mg/kg caffeine 1 hour before session.
- Session duration: About 12.75 minutes plus warm-up.
- Frequency: 6 sessions over 2 weeks.
- Program length: 2 weeks.
- Progression: None.
- Placebo plus SIT.
- Modality: Cycling.
- Work intervals: 30 seconds all-out.
- Recovery: 15 seconds self-paced active recovery.
- Sets or repetitions: 13.
- Intensity: All-out; 5 mg/kg cellulose placebo.
- Session duration: About 12.75 minutes plus warm-up.
- Frequency: 6 sessions over 2 weeks.
- Program length: 2 weeks.
- Progression: None.

## Outcomes

### Post-exercise EE
Status: improved
Caffeine increased post-exercise energy expenditure versus placebo.

469.2 +/- 58.6 vs 392.0 +/- 70.3 kJ, p=0.02.

### Body fat
Status: improved
Body fat decreased in caffeine but not placebo.

Group x time p=0.01; CAF -1.0 +/- 0.7 percentage points.

### Body mass
Status: no clear change
Body mass and BMI did not change in either group.

All p>0.47.

## Practical Insights

- Caffeine may increase post-exercise energy expenditure after all-out SIT, but evidence is narrow.
- The 13 x 30-second/15-second recovery format is intense and best treated as advanced.

## Limitations

- Small sample.
- Physically active men only.
- Short 2-week duration.
- Skinfolds rather than DEXA.
- Baseline body mass and body fat were somewhat higher in caffeine group.

## Safety And Adherence

- No caffeine-related side effects were reported.
- Participants were instructed to report caffeine-related side effects and to avoid caffeine-containing foods/beverages before tests and sessions.
- The study reported successful blinding, with 87% not correctly guessing supplement assignment; no dropout or injury data were otherwise highlighted.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/31826183/) (pubmed)
- [DOI](https://doi.org/10.1590/1414-431X20199169) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6903805/) (full text)

## Agent Guidance

Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.