The EAL is seeking RDNs and NDTRs who work with patients, clients, or the public to treat children and adolescents living with type 1 diabetes, for participation in a usability test and focus group. Interested participants should email a professional resume to by July 15, 2024.

MNT: Weight Management (2015)

Endevelt R, Ben-Assuli O, Klain E, Zelber-Sagi S. The role of dietician follow-up in the success of bariatric surgery. Surgery for obesity and related diseases: official journal of the American Society for Bariatric Surgery; 9: 963-968. PubMed ID: 23499190
Study Design:
Retrospective Cohort Study
B - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
To determine whether dietary counseling can contribute to weight reduction after surgery and to ascertain the minimal number of medical and nutritional treatment visits that patients need to attend to lose at least 5% of their initial BMI (considered clinically significant in most weight reduction studies).  
Inclusion Criteria:
  • Morbidly obese adults who underwent bariatric surgery and were followed between the years 2006 to 2010 in Maccabi Healthcare Services (Israel)
  • Ages 20 years to 70 years at time of surgery; available BMI measurements before and at least one month after surgery.
Exclusion Criteria:
  • Missing baseline BMI or follow-up BMI at least one month post-surgery
  • Pre-defined irrational values of one of the study variables
  • Operation BMI of less than 27 and values over 94
  • BMI in post-op period of less than 24
  • Extreme or irrational values of blood tests
  • Under 20 years or over 70 years of age.  
Description of Study Protocol:


Data collected from computerized medical records.


Restrospective cohort (chart review). Variables collected included:
  • Surgery type
  • Age
  • Gender
  • Anthropometrics
  • Medical history
  • Blood tests
  • Utilization of health care services (number of post-bariatric surgery dietitian counseling sessions, post-bariatric surgery "other expert" counseling sessions, additional operations).

Statistical Analysis

  • Independent samples T-test and chi-square
  • Multivariate logistic regression analysis
  • Linear regression analysis
  • P<0.05 as significant.
Data Collection Summary:

Timing of Measurements

Review of data before and after bariatric surgery.

Dependent Variables

BMI reduction.

Independent Variables

  • Follow-up counseling with dietitian for dietary counseling
  • Pre-surgery BMI
  • Surgery type
  • Age, gender, interval between BMI measurements.

Control Variables

Data extraction methods.

Description of Actual Data Sample:
  • Initial N: 2,976 eligible; 1,680 included after meeting inclusion and exclusion criteria
  • Attrition (final N): 1,680, with 29.6% male
  • Age: 42.3±10.6 years
  • Ethnicity: Not described; presumed Israeli, but race was not described.
  • Baseline BMI: 43.05±5.8
  • Follow-up BMI: 34.3±5.8
  • Location: Tel Aviv, Israel.
Summary of Results:

Key Findings

  • 64.1% LAGB surgery
  • 40.5% attended dietitan counseling post-surgery; 28% received counseling at least twice. Among those attending dieitian visits, the average number of visits was 3.5±3.7 visits.
  • Patients attending at least two dietitian sessions had significantly greater BMI reduction at any level (OR, 2.6; 95%CI, 1.25 to 5.22; P=0.01) and lost 5% of their inital BMI (OR, 1.6; 95%CI, 1.03 to 2.39; P=0.04). These patients also attended more "other expert" sessions (which was adjusted for in analyses in addition to gender, age and interval between BMI measurements). In linear regression analyses, among patients with at least one dietitian visit (N=681), there was a significant association between number of dietitian visits attended and BMI reduction (0.11 reduction in BMI for every visit attended).
Author Conclusion:
Structured nutritional counseling after bariatric surgery can help in achieving clinically significant weight reduction.
Funding Source:
Other: Not Reported.
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.) N/A
  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? Yes
  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? N/A
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  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.) N/A
  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? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? Yes
  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? No
  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? 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)? Yes
  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? ???
  10.1. Were sources of funding and investigators' affiliations described? No
  10.2. Was the study free from apparent conflict of interest? Yes