EAL

NAP: Competition (2007)

Citation:

Okano G, Sato Y, Murata Y. Effect of elevated blood FFA levels on endurance performance after a single fat meal ingestion. Med Sci Sports Exerc. 1998; 30 (5): 763-768.

PubMed ID: 9588621

Study Design:

Randomized crossover trial

Class:

A - Click here for explanation of classification scheme.

Quality Rating:

NEUTRAL: See Quality Criteria Checklist below.

Research Purpose:

To examine the effect of elevated blood FFA levels on CHO oxidation and cycling performance after ingesting a single fat meal.

Inclusion Criteria:

Males who regularly run, swim, cycle, do gymnastics and play baseball were trained for four weeks.

Exclusion Criteria:

None specifically mentioned.

Description of Study Protocol:

Recruitment: Methods not specified
Design: Randomized crossover trial
Blinding used: Not used; lab tests.

Intervention

Two separate occasions separated by one week. Four hours before cycling exercise, subjects consumed either a fat meal (4,711kJ, 30% CHO, 61% fat, 9% protein) or a control meal (4,877kJ, 58% CHO, 31% fat, 11% protein)
The intensity of exercise was 67% of VO_2max for the first 120 minutes of exercise, followed by an increase to 78% VO_2max.

Statistical Analysis

Data concerning physiological and biochemical variables were analyzed by two-way ANOVA with repeated measures (meal x time)
Significant mean differences were located using Fisher's least significant difference procedure
Endurance time and work production were compared using paired T-test.

Data Collection Summary:

Timing of Measurements

Gas exchange collected for one minute before exercise, every 20 minutes during the first 100 minutes of exercise, and at time of fatigue
Blood samples obtained immediately before exercise, every 20 minutes during exercise and at time of fatigue.

Dependent Variables

Gas exchange measurements through Douglas bag
Heart rate through using heart rate monitor
RPE through Borg scale
Blood samples analyzed for glucose, lactate, FFA, triglyceride, insulin.

Independent Variables

Four hours before cycling exercise, subjects consumed either a fat meal (4,711kJ, 30% CHO, 61% fat, 9% protein) or a control meal (4,877kJ, 58% CHO, 31% fat, 11% protein)
During three days preceding the trials, subjects consumed a diet of approximately 12,000kJ per day, 59% CHO, 30% fat, 11% protein
Subjects only exercised on two of three days, rest on day before testing.

Description of Actual Data Sample:

Initial N: Nine males
Attrition (final N): Nine
Age: Mean, 21±1 years
Ethnicity: Not mentioned
Location: Japan.

Summary of Results:

Other Findings

The fat meal ingestion significantly (P<0.05) elevated serum FFA levels above those resulting from control meal ingestion throughout the entire exercise
A significantly lower RER (P<0.05) was observed in the fat meal during the first hour of exercise, which was accompanied by a significantly greater amount of fat oxidized at 20 (P<0.01) and 60 minutes (P<0.05) and a significantly smaller amount of CHO oxidized at 20 minutes (P<0.05)
Endurance time and work production did not differ between trials
There were no significant differences in oxygen consumption, heart rate, RPE or in glucose, lactate and triglyceride levels in the blood.

Author Conclusion:

In summary, elevated serum FFA levels four hours after fat meal ingestion resulted in a lower RER and decreased CHO oxidation during the early stages of prolonged cycling. However, these ergogenic effects were not observed in the later stages of exercise.
As a result, elevated serum FFA levels resulting from fat meal ingestion did not contribute to an enhanced cycling endurance.

Funding Source:

University/Hospital:

Sapporo Medical University (Japan)

Reviewer Comments:

Interventions not isocaloric
Inclusion criteria, exclusion criteria and recruitment methods were not well-defined
Muscle glycogen not measured.

Quality Criteria Checklist: Primary Research
Relevance Questions
	1.	Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies)	Yes
	2.	Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about?	Yes
	3.	Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice?	Yes
	4.	Is the intervention or procedure feasible? (NA for some epidemiological studies)	Yes

Validity Questions
1.	Was the research question clearly stated?		Yes
	1.1.	Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified?	Yes
	1.2.	Was (were) the outcome(s) [dependent variable(s)] clearly indicated?	Yes
	1.3.	Were the target population and setting specified?	Yes
2.	Was the selection of study subjects/patients free from bias?		???
	2.1.	Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study?	No
	2.2.	Were criteria applied equally to all study groups?	???
	2.3.	Were health, demographics, and other characteristics of subjects described?	Yes
	2.4.	Were the subjects/patients a representative sample of the relevant population?	???
3.	Were study groups comparable?		Yes
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	Yes
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	Yes
	3.3.	Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.)	Yes
	3.4.	If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis?	N/A
	3.5.	If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.)	N/A
	3.6.	If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")?	N/A
4.	Was method of handling withdrawals described?		Yes
	4.1.	Were follow-up methods described and the same for all groups?	Yes
	4.2.	Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.)	Yes
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	Yes
	4.4.	Were reasons for withdrawals similar across groups?	N/A
	4.5.	If diagnostic test, was decision to perform reference test not dependent on results of test under study?	N/A
5.	Was blinding used to prevent introduction of bias?		Yes
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	No
	5.2.	Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.)	Yes
	5.3.	In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded?	N/A
	5.4.	In case control study, was case definition explicit and case ascertainment not influenced by exposure status?	N/A
	5.5.	In diagnostic study, were test results blinded to patient history and other test results?	N/A
6.	Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described?		???
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	Yes
	6.2.	In observational study, were interventions, study settings, and clinicians/provider described?	N/A
	6.3.	Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?	???
	6.4.	Was the amount of exposure and, if relevant, subject/patient compliance measured?	Yes
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	Yes
	6.6.	Were extra or unplanned treatments described?	N/A
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	Yes
	6.8.	In diagnostic study, were details of test administration and replication sufficient?	N/A
7.	Were outcomes clearly defined and the measurements valid and reliable?		Yes
	7.1.	Were primary and secondary endpoints described and relevant to the question?	Yes
	7.2.	Were nutrition measures appropriate to question and outcomes of concern?	Yes
	7.3.	Was the period of follow-up long enough for important outcome(s) to occur?	Yes
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	Yes
	7.5.	Was the measurement of effect at an appropriate level of precision?	Yes
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	Yes
	7.7.	Were the measurements conducted consistently across groups?	Yes
8.	Was the statistical analysis appropriate for the study design and type of outcome indicators?		Yes
	8.1.	Were statistical analyses adequately described and the results reported appropriately?	Yes
	8.2.	Were correct statistical tests used and assumptions of test not violated?	Yes
	8.3.	Were statistics reported with levels of significance and/or confidence intervals?	Yes
	8.4.	Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)?	N/A
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	N/A
	8.6.	Was clinical significance as well as statistical significance reported?	Yes
	8.7.	If negative findings, was a power calculation reported to address type 2 error?	No
9.	Are conclusions supported by results with biases and limitations taken into consideration?		Yes
	9.1.	Is there a discussion of findings?	Yes
	9.2.	Are biases and study limitations identified and discussed?	Yes
10.	Is bias due to study's funding or sponsorship unlikely?		Yes
	10.1.	Were sources of funding and investigators' affiliations described?	Yes
	10.2.	Was the study free from apparent conflict of interest?	Yes