"Ounce-equivalents" in the Protein Foods Group: Benefits of Quality: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for "Ounce-equivalents" in the Protein Foods Group: Benefits of Quality (NCT03179462), a randomized na study. The primary outcome is Net Protein Synthesis Rate.

2. Clinical Question

3. Trial Design

The registry describes a randomized, parallel-group study with no masking. Its status is completed. The sponsor is the University of Arkansas. The record gives a start date of 2017-12-01 and a primary completion date of 2018-06-06. It lists enrollment of 27, while the primary outcome results report 8.0 participants in each of the three groups. The record does not explain the relationship between the enrollment figure and the outcome group counts.

The three groups received different protein foods: cooked lean pork, mixed nuts, or tofu. Each group followed diet normalization for 3 days before consuming its assigned food. The registered arm descriptions specify 2 ounces of cooked lean pork, 1 ounce of mixed nuts, and 2 ounces of tofu. No details about randomization sequence generation, allocation concealment, or the conduct of diet normalization are reported in the registry record.

The primary outcome is a continuous measure, reported as a mean with a standard deviation and measured in grams. The posted analysis uses ANOVA to compare all three groups. The record does not describe the sample-size justification or state whether there were interim analyses. It also does not report details about the statistical plan beyond the listed analysis. Although the record lists one outcome measure and one analysis, that information alone does not establish whether additional outcomes or analyses were planned but not posted.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Net Protein Synthesis Rate, measured over Change from 4.5 to 8.5 hours..

The primary endpoint is net protein synthesis rate, reported in grams. The registry describes the measure as determined during a 4.5-hours basal fasted period and a 4-hours post-meal period over an 8.5-hour experimental period. Its stated timeframe is change from 4.5 to 8.5 hours. This makes the endpoint a continuous measure of protein synthesis across the registered measurement periods, rather than a count of events or a time-to-event outcome.

In general, a continuous endpoint can retain information about the range of measured responses, rather than reducing those responses to categories. A mean describes the central value of a group, while a standard deviation describes variability among observations around that mean. Those summaries help readers understand the reported values, but they do not by themselves show the precision of a difference between groups. Confidence intervals for group comparisons would provide information about that precision; none are reported for the primary analysis.

The endpoint is used to compare the responses associated with the three assigned protein-food intakes over the stated period. The registry record does not provide further detail about how the measurement was obtained, how the change was calculated, or how a particular value should be interpreted biologically. The reported results should therefore be read as the registered statistical measure, not as a direct statement about longer-term outcomes or effects outside the experimental period.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the reported ANOVA test?

ANOVA is a general method for comparing means across groups. In this study, the registry lists an analysis of the pork, mixed nuts, and tofu groups. An omnibus ANOVA addresses whether the group means can be treated as equal under the model, rather than directly answering every pairwise question. The reported p <0.05 is the result for that overall analysis. The registry does not report the test statistic, degrees of freedom, model details, or follow-up pairwise tests.

In general, the usual ANOVA model relies on assumptions about the distribution and variability of outcomes and the independence of observations. The registry record does not report assumption checks or explain how these assumptions were assessed. It also does not state whether any transformations or alternative models were considered. These omissions do not change the reported result, but they limit assessment of the analysis from the registry record alone.

How should means and standard deviations be read?

The outcome is continuous, and the registry reports each group using a mean and standard deviation. A mean is a summary of the group’s central value. A standard deviation describes the spread of participant values around that mean. Neither statistic directly provides the estimated difference between two groups or the uncertainty around that difference. In general, confidence intervals for contrasts are useful because they show a range of values compatible with the data and analysis. The registry does not report such intervals for these results.

Variation matters because means are estimates based on observed participants, not exact descriptions of every response in a wider population. The amount of variability and the number of observations both affect precision. The posted outcome group counts are 8.0 for each group. The registry does not state whether all randomized participants contributed to the endpoint analysis or how any missing measurements were handled.

What does an overall p-value establish?

In general, a p-value is calculated relative to a statistical model and a null hypothesis. It indicates how compatible the observed data are with that null model, conditional on the assumptions used. A small p-value can provide evidence against the null model, but it is not an estimate of effect size and does not by itself establish the importance of an effect. Here, p <0.05 pertains to the overall ANOVA. It does not specify which food-group comparisons account for the overall result.

Multiplicity is relevant whenever several hypotheses or comparisons are evaluated. Testing multiple pairwise contrasts can increase the chance of at least one false-positive finding unless the analysis accounts for that multiplicity. The registry reports one ANOVA and does not report pairwise tests or a multiplicity procedure. It is therefore not possible to infer from this record how a set of pairwise comparisons would have been handled.

How should planning illustrations be interpreted?

Sample-size illustrations based on an observed effect are planning calculations, not observed trial results and not observed power. In general, they describe the number of participants that a hypothetical future study might require under stated assumptions. The stated planning approach uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. These illustrations are not the trial’s own design justification. The registry record does not report the original sample-size justification or its design assumptions.

Planning based on an effect observed in a small study can be uncertain, because the observed estimate itself may vary. Such an illustration should not be read as evidence that the completed study had a particular probability of detecting an effect. The registry does not provide a sponsor-planned target for the primary outcome in the record.

What cannot be assessed from the analysis record?

The record does not report the analysis population definition, missing-data methods, allocation-concealment procedures, or detailed model specification. It also does not state whether there were interim analyses. In general, these details help readers understand how participants and outcomes entered the analysis and whether the model matched the design. Without them, interpretation is limited to the posted group summaries and the overall ANOVA result. The record identifies a randomized, unmasked, parallel design, but does not provide enough information to assess every aspect of implementation or analysis.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Pork Intake", "Mixed Nuts Intake", "Tofu Intake")
n   <- c(8, 8, 8)
m   <- c(8.65, 1.97, 5.69)
sp  <- c(1.6, 1.04, 0.54)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Pork Intake  8  8.650  1.600  7.312  9.988
CARM  Mixed Nuts Intake  8  1.970  1.040  1.101  2.839
CARM  Tofu Intake  8  5.690  0.540  5.239  6.141

11. Analyses Reported by the Sponsor

The registry’s own posted analysis is an ANOVA comparing the three groups, with p <0.05. That analysis is the sponsor-reported result and takes precedence over any simple recalculation from summary statistics if a discrepancy is present. The registry does not flag a discrepancy. The outcome summaries are means and standard deviations for each group, but they are not a substitute for the reported analysis.

The registry does not report pairwise comparison estimates, confidence intervals, or p-values for individual group contrasts. It also indicates that values are missing or not estimable for a two-arm comparison of this continuous endpoint. Accordingly, the reported overall ANOVA should not be described as establishing the result of a particular two-group comparison. No recalculated two-arm estimate can be interpreted from the registry record.

In general, a recalculation from summary statistics may use a simplified, unadjusted method and may not reproduce a sponsor’s full analysis if that analysis used other information or a different model. Here, the available result to interpret is the sponsor’s posted omnibus ANOVA, alongside the group means and standard deviations. The record does not provide enough detail to reconstruct further comparisons or evaluate whether they were part of the sponsor’s analysis.

12. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome measure and one reported analysis. The reported analysis is an ANOVA across three groups. The record does not describe a broader testing plan, identify secondary outcomes, or report a multiplicity adjustment. It also does not report pairwise tests. An overall ANOVA can address whether there is evidence of any group-level difference, but it does not answer each possible pairwise question. If multiple contrasts were tested, the approach to controlling multiplicity is not reported in the registry record.

The record does not report how missing outcome data were handled, whether any participants were excluded from the endpoint analysis, or the analysis population definition. The group outcome summaries list 8.0 participants for each arm, while the overall enrollment is 27. The registry does not explain this relationship. The safety figures use different at-risk counts by group; the record does not explain how those counts relate to the outcome population or enrollment.

Randomization is listed, but the registry does not report the method used to generate the sequence or how allocation was concealed. Masking is listed as none. The record also does not describe interim analyses, protocol deviations, or sensitivity analyses. These are limits on what can be assessed from the posted information; they do not establish that a particular procedure was or was not conducted. The sample-size justification is not reported in the registry record, so the adequacy of the planned enrollment for the primary analysis cannot be evaluated from this information.

13. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry reports no serious adverse events in the listed groups: 0 of 9 at risk in the pork group, 0 of 10 at risk in the mixed nuts group, and 0 of 8 at risk in the tofu group. It also reports 0 deaths in each group. For other adverse events, the figures are 0 of 9, 0 of 10, and 0 of 8, respectively. These are the counts posted in the safety record.

Zero observed events does not establish that an event cannot occur. In general, adverse-event counts are interpreted in light of how many participants were monitored, the duration and completeness of monitoring, and how events were defined and collected. The registry record does not report additional details about adverse-event definitions, surveillance, or duration. It also does not explain why the at-risk counts differ across groups or how they relate to the enrollment and primary outcome counts.

These figures describe recorded events in this study, not a general estimate of safety in other populations or settings. They should not be used alone to make a broader safety conclusion.

14. What the Result Does, and Does Not, Mean

The posted results describe net protein synthesis rate after three assigned protein-food intakes during a short experimental period. The group means are 8.65 grams for pork, 1.97 grams for mixed nuts, and 5.69 grams for tofu, with reported standard deviations of 1.6, 1.04, and 0.54. An ANOVA across the three groups is reported with p <0.05. In statistical terms, this is an overall result indicating evidence of differences among group means under the reported analysis.

The result does not establish which specific pair or pairs differ. The registry does not report pairwise estimates, confidence intervals, or pairwise p-values. It also does not give enough information to judge the precision of particular contrasts. The group means and standard deviations describe the observed groups, but do not alone provide a complete inferential comparison.

The finding is limited to the registered foods, amounts, participants, and experimental period. The registry describes young, healthy adults, but provides no further participant characteristics in the record summarized. It does not report follow-up beyond the stated measurement period or outcomes beyond the listed primary measure. The record therefore cannot establish whether the observed group-level pattern applies to other populations, amounts, dietary settings, or longer time periods.

In general, a statistically detectable difference and a practically important difference are distinct questions. The posted p-value does not quantify practical importance, and the registry provides no threshold for interpreting the magnitude of the endpoint. The results should be understood as an overall statistical comparison of the registered outcome, not as a clinical recommendation or a definitive statement about long-term effects.

15. Why This Trial Matters Statistically

This trial is statistically useful as an example of the distinction between an omnibus test and pairwise comparisons. The registry reports three group means and an overall ANOVA result. That analysis can indicate evidence of a difference somewhere among the groups, but it does not identify the specific comparisons responsible. Readers should not infer pairwise conclusions from the omnibus p-value alone.

The record also illustrates why a p-value is not a complete report of an effect. Means and standard deviations describe the observed outcome values, while comparison estimates and confidence intervals would communicate the magnitude and precision of differences more directly. Those comparison estimates are not reported in the registry record. Consequently, the evidence can be described at the overall-test level, but the size and precision of specific contrasts remain unclear.

Another statistical issue is the distinction between trial design and planning calculations based on observed results. Planning illustrations can help describe hypothetical future studies under stated assumptions, but they are not observed power and do not establish the original design rationale. The registry does not report the study’s sample-size justification.

Finally, the record lists randomized allocation and no masking, while leaving several implementation and analysis details unreported. The outcome group counts, enrollment figure, and safety at-risk counts do not have an explanation in the record. These gaps matter for evaluating the analysis population and the scope of the reported summaries. The trial therefore offers a clear example of how much can—and cannot—be concluded from registry-level results.

16. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The registry record provides limited detail about the study methods. It does not report eligibility criteria beyond the summary’s description of young, healthy adults, nor does it provide participant characteristics. The procedures for random sequence generation and allocation concealment are not reported. Masking is listed as none, but the record does not discuss whether outcome measurement or other study activities were conducted with safeguards against bias.

The analysis information is also limited. The registry reports an overall ANOVA, but not its model specification, test statistic, degrees of freedom, assumption checks, or covariate adjustment. It does not report pairwise comparisons or confidence intervals. Missing-data methods, the analysis population, protocol deviations, and sensitivity analyses are not reported in the registry record. The sample-size justification and any interim analyses are also not reported.

The registry lists enrollment of 27, while the primary outcome results report 8.0 participants per group. The safety at-risk counts are 9, 10, and 8. The record does not explain these differences in counts, so the relationship among enrollment, outcome analyses, and safety monitoring cannot be determined from the posted information.

The outcome description gives a short experimental measurement period, with change from 4.5 to 8.5 hours and a basal fasted and post-meal measurement description. No longer-term outcome is listed. These limitations mean the results should be interpreted narrowly: as the posted summaries and overall statistical test for this registered endpoint, rather than as a complete account of individual comparisons, longer-term effects, or broader applicability.

17. Related Tutorials

18. Related Statistical Calculators

19. Sources

• ClinicalTrials.gov: "Ounce-equivalents" in the Protein Foods Group: Benefits of Quality — NCT03179462.
• Registry record last updated 2021-12-06; status last verified 2021-10.
• Results first posted 2021-09-30.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

20. Record Summary

This completed randomized, unmasked, parallel-group study was sponsored by the University of Arkansas. The registry describes intake of cooked lean pork, mixed nuts, or tofu following diet normalization for 3 days. Enrollment is listed as 27.

The primary outcome is net protein synthesis rate in grams, described as change from 4.5 to 8.5 hours. The posted group means are 8.65 for pork, 1.97 for mixed nuts, and 5.69 for tofu; the respective standard deviations are 1.6, 1.04, and 0.54. Each outcome group is listed with 8.0 participants. The registry reports an overall ANOVA with p <0.05, but no pairwise estimates or confidence intervals.

The record reports 0 serious adverse events and 0 deaths in each listed group. It does not explain the differences between enrollment, outcome counts, and safety at-risk counts, or report the analysis population and missing-data methods.