The Effects of Exercise on Dietary Intake: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for The Effects of Exercise on Dietary Intake (NCT00943436), a non-randomized na study. The primary outcome is Energy Intake at the Meal (Exercise Session).

2. Clinical Question

3. Trial Design

The study is registered as a completed, non-randomized crossover study of exercise and rest sessions in college-aged males. Its stated purpose is to determine whether energy and macronutrient intake changes when comparing habitually active and habitually sedentary males across a resting session and an exercise session. The registered intervention names are “Exercise Session” and “Rest Session.” The record describes two lifestyle groups, active males and inactive males, whose activity definitions refer to behavior during the last month.

The enrollment is 20. The adverse-event information lists 10 participants at risk in each lifestyle group. The registry classifies allocation as non-randomized and masking as none. Thus, the comparison between the active and inactive groups is observational with respect to habitual lifestyle; it is not a randomized comparison of those groups. Differences between them could reflect factors beyond activity classification, and the record does not specify an adjustment strategy that would address such differences.

The crossover designation indicates that the study concerns more than one session condition, but details needed to understand the within-participant structure are not reported in the registry record. The order of the sessions, any washout interval, whether all participants completed both sessions, and the allocation process are not reported in the registry record. The stated model therefore should not be taken as sufficient information to reconstruct how the observations were analyzed.

The primary outcome is energy intake at the meal during the exercise session. Eight outcome measures are listed, while no statistical analyses are listed. The registry gives no numerical primary-outcome result. The posted record also does not report the study’s sample-size justification, a detailed statistical analysis plan, or analysis-population definitions.

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.

Before assignment: Participants were randomly assigned to which session, exercise or rest, they engaged in first. As this is a crossover design, participants did complete both the exercise and rest conditions.

Exercise Session: 45 Minutes of Activity

Rest Session: 45 Minutes of Reading

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 Energy Intake at the Meal (Exercise Session), measured over 2 hours.

The primary endpoint is “Energy Intake at the Meal (Exercise Session),” measured in kilocalories over a 2-hour timeframe. It is a continuous measure summarized as a mean with a standard deviation. The endpoint describes the amount of energy consumed at the meal associated with the exercise session; it is not itself a direct measure of energy expenditure or long-term dietary behavior.

According to the registry description, each item served at an ad libitum buffet meal was weighed before and after the participant ate. The difference was used to determine the gram weight consumed for each item. Food labels and NDS-R software were then used to determine dietary intake based on the amount of each food consumed. This approach is intended to quantify meal intake from the foods eaten rather than relying only on a participant’s estimate of how much was consumed.

A meal-level energy measure is relevant to the stated question because the study concerns whether intake changes around exercise and rest sessions and whether patterns differ by habitual activity. However, the registry does not report the observed mean, standard deviation, or a comparison estimate for this primary endpoint. The magnitude, direction, and precision of any difference are therefore not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What kind of outcome is the primary measure?

General statistical explanation: A continuous outcome can take values along a measurement scale, rather than being limited to categories such as event or no event. The registry treats meal energy intake as continuous and specifies a mean and standard deviation. The mean describes the central level of measurements in a group, while the standard deviation describes how spread out individual measurements are around that group’s mean. These are descriptive quantities; by themselves, they do not establish a difference between groups or sessions.

For this study, the registry names energy intake in kilocalories as the primary endpoint and gives a 2-hour timeframe. The measurement procedure uses food weights before and after the meal, together with food labels and NDS-R software, to estimate dietary intake. The numerical mean and standard deviation are not reported in the registry record, so those summaries cannot be interpreted for this trial.

Why does the crossover designation matter?

General statistical explanation: In a crossover design, the same participant may contribute measurements under more than one session condition. Those measurements can be correlated because they come from the same person. A paired analysis uses the within-person relationship; an analysis that assumes independent observations may not reflect that structure. Which approach is appropriate depends on the actual design and data, including whether participants completed each condition and how sessions were ordered.

The registry classifies this study as crossover and identifies exercise and rest sessions. It does not report session order, a washout interval, completion by session, or the analysis used to account for repeated measurements. It lists no statistical analyses. Therefore, the analysis structure and its handling of within-participant dependence are not reported in the registry record. The crossover label alone is not enough to identify the statistical test or model.

How should the active and inactive groups be understood?

General statistical explanation: Random assignment helps create comparable groups, on average, for a treatment comparison. When allocation is non-randomized, group differences can also reflect pre-existing characteristics associated with group membership. Statistical adjustment may address measured differences under suitable assumptions, but it cannot automatically remove bias from unmeasured factors.

The registry records non-randomized allocation and defines active and inactive groups using habitual activity during the last month. It does not report covariate adjustment or a method for controlling confounding. Consequently, the two lifestyle groups should not be interpreted as equivalent to randomized treatment arms. The record’s own note also cautions that the arms are not a like-for-like control comparison.

What can a confidence interval or p-value tell a reader?

General statistical explanation: A confidence interval communicates the range of effect values compatible with the data and the specified statistical procedure. Its width reflects precision: a wider interval indicates less precision than a narrower interval. A p-value measures how incompatible the data are with a particular null hypothesis under the assumptions of the test; it does not measure the size or importance of an effect. Neither statistic replaces the estimated effect itself.

No confidence interval, p-value, or estimated comparison for the primary endpoint is reported in the registry record. There is therefore no basis in the posted results for describing statistical significance or precision. A non-significant result, if one existed, would not by itself demonstrate equivalence or absence of an effect; equivalence requires an appropriate question and analysis, neither of which is reported.

What does the sample-size illustration represent?

General statistical explanation: A sample-size calculation is a planning exercise based on assumptions about the effect to detect, variability, significance level, allocation, and analysis method. It is not a result from participants and should not be interpreted as observed power. A calculation based on an effect estimated from a study is especially dependent on that estimated effect and does not establish that the study’s original design was justified by that calculation.

The registry describes planning illustrations based on a fraction of an observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It states that the illustrations are not the trial’s own design. The primary outcome result needed to understand an observed-effect-based illustration is not reported in the registry record. The actual sample-size justification is also not reported in the registry record.

These methodological distinctions matter because the study has a crossover designation but the planning description refers to equal allocation between two arms. Without the detailed calculation and its analysis assumptions, the illustration cannot be treated as a reconstruction of the trial’s design or as evidence about the trial’s achieved precision. The registry does not report an observed-power 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("Active Lifestyle Males", "Inactive Lifestyle Males")
n   <- c(10, 10)
m   <- c(1105.6, 934.8)
sp  <- c(389.2, 222)
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  Active Lifestyle Males  10  1105.600  389.200  827.183  1384.017
CARM  Inactive Lifestyle Males  10  934.800  222.000  775.991  1093.609

11. Multiplicity, Missing Data and Analysis Populations

The registry lists eight outcome measures. When several outcomes are examined, the chance of at least one apparently notable finding can increase if each is tested independently without an appropriate strategy. General statistical explanation: Multiplicity approaches may define a primary outcome in advance, adjust inference across a family of tests, or distinguish confirmatory analyses from exploratory ones. The suitable approach depends on the study question and analysis plan.

Although the registry identifies energy intake at the meal during the exercise session as the primary outcome, it does not report a multiplicity strategy or explain how the other listed outcomes relate to that endpoint. The registry lists no statistical analyses. The handling of multiple outcomes, comparisons, or time points is therefore not reported in the registry record. No interim analyses are reported in the registry record.

The record also does not report how missing outcome measurements were handled, whether participants were excluded from any analysis, or which analysis populations were defined. It is not possible to determine from the registry record whether all enrolled participants contributed to each endpoint, whether observations from both sessions were required, or whether any imputation method was used. These details can affect the interpretation of a mean or comparison, especially in a crossover study where the availability of measurements across sessions may matter.

The status is completed and enrollment is 20, but neither fact specifies the number analyzed for the primary endpoint. The number of analyses listed is zero; that indicates the registry does not list statistical analyses, not that no analysis was conducted outside the registry. Sample-size justification, analysis-set definitions, missing-data procedures, and multiplicity handling are not reported in the registry record.

12. Safety Results

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

Other (non-serious) adverse events

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

The registry’s adverse-event information lists the active-lifestyle group and the inactive-lifestyle group separately. For each group, 10 participants are listed as at risk, zero as affected by serious adverse events, and zero as affected by other adverse events. These are the event counts recorded for those categories in the registry.

A zero count means that no affected participants are recorded for that category in the posted information. It should not be read as proof that an event was impossible, or as a complete description of every safety outcome that might have been collected. The record does not provide additional details about event definitions, collection procedures, follow-up for safety, or the relationship of any event to a session.

The death fields are null rather than numerical counts. Accordingly, deaths are not reported in the registry record; a null field is distinct from a reported zero. The registry also does not list serious-event terms. These limited counts should be interpreted as registry reporting, not as a comprehensive assessment of safety.

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

The registry record describes a study designed to examine energy and macronutrient intake in college-aged males across exercise and rest sessions, with participants grouped by habitual activity. It specifies a primary endpoint: energy intake at the meal during the exercise session, measured in kilocalories over a 2-hour timeframe. It also describes a weighing-based procedure for estimating the food consumed.

What the posted record does not establish is the primary outcome result. No group mean, standard deviation, effect estimate, confidence interval, or p-value is reported for that endpoint. Therefore, the record cannot show the direction or magnitude of an intake difference, how precisely a difference was estimated, or whether a statistical test supported a particular conclusion. The listed study purpose is not itself evidence of an observed result.

The design labels also constrain interpretation. The study is non-randomized, and active and inactive status is based on habitual activity. Any observed difference between these groups, if reported elsewhere, would not by itself demonstrate that activity status caused the difference. The crossover designation suggests session-level repeated measurements, but the record does not describe the order, completion, or statistical handling of those measurements.

The posted adverse-event counts record zero serious and zero other affected participants in each lifestyle group, with 10 at risk in each. The death fields are not reported. These entries do not answer the efficacy question, and they should not be expanded into a broader safety claim than the registry data support.

In short, the record documents the question and parts of the design but does not supply the numerical outcome evidence required to assess the primary result. It cannot establish that exercise changed intake, that it did not change intake, or that the active and inactive groups had similar intake.

14. Why This Trial Matters Statistically

This study illustrates why a registry record should be read as more than a statement of its research question. The entry identifies the target population, session conditions, primary endpoint, measurement procedure, and non-randomized allocation. Those details help readers understand what the investigators intended to examine and what type of measurement was planned.

At the same time, an identified endpoint does not guarantee that its result is available in the registry. Here, the primary outcome is described, but its numerical summaries and inferential analysis are not reported in the registry record. That distinction is statistically important: without an effect estimate and a measure of uncertainty, readers cannot assess either the size of a pattern or the precision of the evidence.

The crossover label and non-randomized lifestyle groups also highlight two different comparison structures. Repeated sessions within participants may call for analysis that accounts for within-person dependence, while comparisons between habitual activity groups remain vulnerable to differences unrelated to the study sessions. The registry does not report the analysis details needed to evaluate either issue.

Finally, the entry lists multiple outcomes and limited adverse-event counts, but does not report multiplicity handling, missing-data procedures, analysis populations, or a detailed statistical plan. These omissions do not establish that such procedures were absent from the research; they mean that the registry record does not allow readers to assess them. The example underscores the value of complete outcome and analysis reporting for transparent interpretation.

15. 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 central limitation for statistical interpretation is that the registry record does not report numerical results for the primary endpoint. The outcome is named and its measurement procedure is described, but no mean, standard deviation, comparison estimate, confidence interval, or p-value is posted. The effect’s direction, size, and precision cannot be evaluated from this record.

The record classifies the study as non-randomized. The active and inactive groups are defined by habitual activity, so a group comparison is not a randomized estimate of the effect of assigning an activity pattern. The registry does not report adjustment for other characteristics or provide details that would support a causal interpretation.

Although the study model is listed as crossover, important design details are not reported in the registry record. Session order, washout, completion across conditions, and the statistical approach to repeated observations are not specified. These omissions limit assessment of whether the analysis reflects the within-participant structure.

Eight outcome measures are listed, but results for them and a multiplicity strategy are not reported. Missing-data handling, analysis populations, protocol deviations, and the statistical analysis plan are also not reported in the registry record. Enrollment is listed as 20, but the number included in each outcome analysis is not given.

The adverse-event entries contain zero counts for affected participants in the serious and other categories, but the record does not provide event definitions or additional safety detail. Death fields are null and therefore not reported. These limitations concern what can be learned from the registry record; they do not establish what information may exist outside it.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: The Effects of Exercise on Dietary Intake — NCT00943436.
• Registry record last updated 2018-06-29; status last verified 2018-04.
• Results first posted 2011-07-13.
• 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.

19. Record Summary

The registry record describes a completed, non-randomized crossover study of 20 college-aged males, comparing exercise and rest sessions and distinguishing active-lifestyle from inactive-lifestyle participants. The primary endpoint is energy intake at the meal during the exercise session, measured in kilocalories over a 2-hour timeframe using food weights, labels, and NDS-R software.

The record lists eight outcome measures and no statistical analyses. It does not report the primary endpoint’s numerical result, inferential statistics, sample-size justification, missing-data procedures, or analysis populations. Serious and other adverse-event counts are zero in both lifestyle groups, with 10 at risk in each; deaths are not reported. The available registry information describes the study question and some design features but does not permit a quantitative interpretation of the primary outcome.