NAP: Energy Balance and Body Composition (2014)


Artioli GG, Iglesias RT, Franchini E, Gualano B, Kashiwagura DB, Solis MY, Benatti FB, Fuchs M, Lancha AH Jr. Rapid weight loss followed by recovery time does not affect judo-related performance. J Sports Sci. 2010; 28 (1): 21-32.

Study Design:
Before-After Study
D - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To determine whether rapid weight loss achieved by typical diets and followed by a four-hour recovery period would affect the high-intensity, judo-related anaerobic performance of weight cyclers. 

Inclusion Criteria:
  • Male
  • Judo competitors actively competing at regional level or above.


Exclusion Criteria:
  • Female
  • Males not competing in judo competitions
  • Regular use of laxatives, diuretics or diet pills.
Description of Study Protocol:
  • Controlled non-randomized trial
  • Athletes familiar with rapid weight loss procedures (weight cyclers, weight loss group) vs. athletes not familiar with rapid weight loss procedures (non-weight cyclers, control group).
  • Weight loss group: Body weight loss of 5% of body weight in a five-day period using subject's usual methods. Laxatives, diuretics and diet pills were not allowed. Food records were completed during the last three days. 
  • Control group: Maintained usual food and fluid intake patterns as well as completed a food record, but did not reduce body weight.   

Statistical Analysis

  • Mixed-model, two-way (time x group) analysis of variance (ANOVA)
  • Four different covariance structure matrices were tested and Schwarz's Bayesian criterion was used to choose the best model for each data set
  • When significant main effects were observed, a Tukey post-hoc test was performed
  • Non-paired Student's T-test was done for food intake data
  • SAS proc IML was used to perform a simulation to determine the power of the statistical test.   
Data Collection Summary:

Timing of Measurements

Pre- and post-intervention, five to seven days apart.

Dependent Variables

  • Body composition: Underwater weighing
  • Plasma glucose, lactate, hematocrit: From earlobe during a rest period, three minutes after tuchi-komi exercises, three minutes after combat and three minutes after the final Wingate bout. For weight loss group at post-intervention, resting blood samples were taken before the simulated weigh-in.
  • Performance: Structure pattern in combats (total ground work, total standing combat time, total effort time, total recovery time) and number of attacks during judo combats; wingate mean and peak anaerobic power.

Independent Variables

Weight loss of 5% of body weight in five-day period using subject's usual methods vs. no weight loss.

Control Variables

  • Abstinence from alcohol, caffeine and intense exercise in 24 hours preceding assessments
  • Well hydrated and in fed state for assessments
  • Weight loss group was instructed to re-feed and rehydrate for four hours prior to performance evaluation
  • Performance of situations highly specific to those in an actual judo environment, effort and recovery patterns similar to judo combats
  • Ergometric testing used previously for assessing judo athletes. 
Description of Actual Data Sample:
  • Initial N: 14 males
  • Attrition (final N): 14
  • Age: 20±4 years  for weight loss and 22±4 years for controls
  • Other relevant demographics: Judo experience; there was no significant difference between groups (12±4 vs. 13±3 years in weight loss and control groups, respectively)
  • Anthropometrics: No significant differences:
    • 77.9kg±12.2kg (weight loss) and 67.3kg±12.2kg (controls) body weight
    • 1.75m±0.06m (weight loss) and 1.75m±0.06m (controls) height, respectively.   
  • Location: Sao Paulo, Brazil.
Summary of Results:


  • Weight loss group used a combination of severe energy restriction and hypohydration-inducing methods. They reduced their body weight by 4.8%±1.1% from pre- to post-intervention (P<0.001). Controls maintained a stable weight. The weight loss group ate significantly less CHO, fat and protein than the controls (P<0.001).
  • During the four-hour recovery, the weight loss group ingested 1,391kcal±375kcal (201g±62g CHO; 50g±16g fat; 34g±23g protein). After the recovery, weight loss athletes regained 51%±13% of their lost weight. 
  • Weight loss athletes had a significant decrease in body fat (8.8kg±2.6kg vs. 8.0kg±2.3kg, P<0.01) and lean body mass (66.2kg±4.6kg vs. 63.5lg±4.9kg, P<0.01). No differences were seen in the control group.    
  • There were no group or time main effects of interaction effect for time structure patterns in the combats. No significant difference was observed between groups in the number of attacks during judo combats. 
  • No main group or interaction effects were observed for all of the Wingate performance variables
  • No main or interaction effects were seen for hematocrit by group or test occasion. Resting plasma glucose was significantly lower in the weight loss group after the intervention compared with baseline, but no other differences were observed between groups or conditions. Plasma lactate did not differ between groups or conditions.
Author Conclusion:

Rapid weight loss (approximately 5% body weight) did not affect judo-related performance in experienced weight cyclers when the athletes had four hours to recover. 

Funding Source:
Reviewer Comments:
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? Yes
  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? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  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? Yes
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%.) N/A
  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? No
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? Yes
  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? Yes
  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? Yes
  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? N/A
  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? N/A
  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? N/A
  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? N/A
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