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Adult Weight Management

AWM: Meal Replacements (2006)

Citation:

Winick C, Rothacker DQ, Norman RL.  Four worksite weight loss programs with high-stress occupations using a meal-replacement product.  Occup Med 2002; 52(1): 25-30.

 
Study Design:
Longitudinal Study, Nonrandomized Clinical Trial
Class:
C - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:
To investigate workers in high-stress occupations seeking to achieve weight loss by the use of a meal replacement regimen.
Inclusion Criteria:
General healthy, overweight (15-45% above IBW) men and women working in high-stress occupations (urban police, hospital health professionals, commercial airplane pilots and flight attendants, and suburban firefighters).  The work culture of these groups typically includes environmental hazards, rotating work shifts with irregular meal schedules and circadian disruption, and potential life-and-death emergencies.
Exclusion Criteria:
Excluded were people taking prescribed medication other than birth control pills, subjects with clinical or endocrine disease, or surgical conditions, substance abusers, females who were pregnant, lactating or engaging in unprotected sexual intercourse, recent participants in a weight reduction program, and recent users of any investigational drugs.
Description of Study Protocol:

Recruitment

Employees invited to attend an informational dinner meeting about the study.  For hospital personnel, a detailed flyer was distributed.

Design

Longitudinal study.

Blinding used (if applicable)

Not applicable.

Intervention (if applicable)

2 meal replacements daily with subjects choosing a third "sensible" meal for 12 weeks.

Statistical Analysis

Weight and attitudinal data tabulated for each occupational group.  Attrition rates and weight changes were compared with those reported for the 3 comparison groups.  Because of the demographic differences between the clinical and occupational groups, and the absence of a full database on the clinical subjects, we did not compute the statistical significance of differences between the 2 groups in retention and weight loss.  Statistical analyses were conducted with the data on the occupational subjects.

Data Collection Summary:

Timing of Measurements

Subjects received meal replacements weekly and were weighed weekly.  Questionnaires regarding their experience with the product were completed weekly and after week 12.

Dependent Variables

  • Body weight weighed on same scales

Independent Variables

  • Meal replacements:  each participant received 14 portion-controlled servings of Slim Fast powder for each week, along with 12 snack bars.  Subjects did not pay for the product.  Subjects were to consume 2 meal replacements, 1 sensible meal, and 2 snacks (either fruits or vegetables or the snack bars), for a maximum of ~1160 kcal/day.  There were no counseling sessions or exercise recommendations.

Control Variables

 

Description of Actual Data Sample:

Initial N: 492 subjects.  286 police officers (251 male, 35 female) at 38 precincts in New York City, 31 firefighters (31 male) at 2 firehouses in Connecticut, 150 physicians, nurses and other personnel (18 male, 132 female) at a hospital in Florida, and 25 pilots and flight attendants (9 male, 16 female) based in New Jersey.  Compared to subjects from 3 previous clinical studies using the same meal replacement product over 12 weeks.

Attrition (final N):  See above.

Age:  Mean group ages ranged from 32.17 +/- 5.70 years to 44.50 +/- 16.40 years  

Ethnicity:  Not mentioned. 

Other relevant demographics:  Mean group BMIs ranged from 27.40 +/- 2.54 to 32.90 +/- 3.39 

Anthropometrics (e.g., were groups same or different on important measures)

Location:  See above.

 

Summary of Results:

 

Occupation

Completing Mean BMI Mean BMI loss Mean weight (kg) Mean weight loss (kg)
Police - male 216 (76%) 29.96 +/- 3.32 2.61 96.40 +/- 13.21 8.62 +/- 5.30
Police - female 24 (69%) 25.83 +/- 3.52 3.02 71.77 +/- 13.12 6.81 +/- 4.40
Health care - male 15 (83%) NA NA 95.45 +/- 18.45 6.37 +/- 2.90
Health care - female 81 (61%) NA NA 78.60 +/- 18.00 4.35 +/- 3.40
Flight crew - male 8 (89%) 29.46 +/- 4.98 2.99 88.92 +/- 7.61 10.48 +/- 2.30

Flight crew - female

14 (88%) 24.80 +/- 2.89 2.60 65.97 +/- 10.63 7.07 +/- 3.90

Firefighters - male

22 (71%)

29.30 +/- 3.13 3.60

90.90 +/- 1.00

11.15 +/- 4.60

Other Findings

Completion rate for the 12 weeks was 79.8%.

Reductions in mean weight and mean BMI were greater than in medically supervised clinical trials with non-worksite adults (mean weight loss of 7.34 kg and BMI loss of 2.68 for occupational subjects vs 6.88 kg and 2.28 for clinic subjects).

Firefighters lost the most weight (R2 = 0.230, P < 0.014) and medical personnel the least (R2 = 0.072, P < 0.001).

Follow-up found considerable retention of weight loss.

Men lost significantly more weight than women (P < 0.006).

Author Conclusion:
We conclude that employees in some high-stress settings may participate productively in worksite weight reduction and maintenance programs that use meal replacements.  The results of this study suggest that further data on this approach could be useful in occupational medicine.
Funding Source:
Industry:
Slim-Fast
Food Company:
Reviewer Comments:
Compliance not monitored.  Basically a comparison of occupational vs clinic setting with use of meal replacements.
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? ???
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) No
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? ???
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) No
  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? ???
  4.1. Were follow-up methods described and the same for all groups? ???
  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%.) ???
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? ???
  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? 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.) No
  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? 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? Yes
  6.6. Were extra or unplanned treatments described? No
  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? ???
  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