Adult Weight Management

MNT: Weight Management (2015)

Citation:

Ashley JM, Herzog H, Clodfelter S, Bovee V, Schrage J, Pritsos C. Nutrient adequacy during weight loss interventions: A randomized study in women comparing the dietary intake in a meal replacement group with a traditional food group. Nutrition Journal 2007; 6: 12.

PubMed ID: 17592648
 
Study Design:
Randomized Controlled Trial
Class:
A - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To document and compare the macronutrient and micronutrient levels in the foods chosen by women following two different weight-reduction interventions.

Inclusion Criteria:
  • Generally healthy overweight or obese women
  • Aged 25 to 50 years
  • BMI 25 to 35kg/m2.
Exclusion Criteria:
  • Current chronic or psychological disease
  • Abnormal serum laboratory values of clinical significance
  • Current hormone replacement therapies
  • Pregnant, planning to become pregnant or lactating
  • Planning to move out of the area within the following year
  • Currently participating in a weight loss program.
Description of Study Protocol:

Recruitment

Subjects were selected from those responding to media recruitment in the local university community. All subjects completed the intervention during 2002 and 2004. 

Design 

Randomized Clinical Trial. Subjects randomized to Traditional Food Group or Meal Replacement Group

Blinding used 

Not possible, implied with laboratory measures 

Intervention

  • Traditional Food Group: Self-selection of conventional foods for meal and snacks using the USDA Food Guide Pyramid 
  • Meal Replacement Group: Self-selection of meal and snacks using the USDA Food Guide Pyramid, incorporating one to two meal replacement drinks or bars per day
  • Both groups had energy-restricted goal of 1,200kcal/day
  • Dietary intake data was obtained using three-day food records kept by subjects at baseline, six months and one year
  • Each diet intervention consisted of 18 small group sessions led by the same Registered Dietitian, including bi-monthly classes (12) for the first six months, followed by monthly classes (six) for the last six months of intervention
  • Subjects received the LEARN Program manual for Weight Control, with those in the Meal Replacement Group receiving the Meal Replacement edition. 

Statistical Analysis

  • Study design based on sample of 96 subjects which would yield a power of 80% assuming a two-sided type I error rate of 5%, accounting for a standard 20% attrition rate, but the study attrition rate was 27% at one year
  • Analyses on all enrolled subjects were conducted using two intent-to-treat methods: Last weight carried forward and baseline weight carried forward, remaining analyses conducted on completers
  • All analyses comparing between group differences used independent T-tests
  • Analyses focused on change within each group used paired T-tests.
Data Collection Summary:

Timing of Measurements

Measurements were taken at baseline, six months and 12 months.

Dependent Variables

  • Weight
  • Height measured using wall-mounted stadiometer
  • Waist circumference measured using non-stretchable measuring tape
  • Body composition measured through bioimpedance scale
  • Fasting blood samples
  • Blood pressure measured using digital manometer machine.

Independent Variables

  • Traditional Food Group: Self-selection of conventional foods for meal and snacks using the USDA Food Guide Pyramid 
  • Meal Replacement Group: Self-selection of meal and snacks using the USDA Food Guide Pyramid, incorporating one to two meal replacement drinks or bars per day
  • Both groups had energy-restricted goal of 1,200kcal per day
  • Dietary intake data was obtained using three-day food records kept by subjects at baseline, six months and one year
  • Each diet intervention consisted of 18 small group sessions led by the same Registered Dietitian, including bi-monthly classes (12) for the first six months, followed by monthly classes (six) for the last six months of intervention
  • Subjects received the LEARN Program manual for Weight Control with those in the Meal Replacement Group receiving the Meal Replacement edition. 

Control Variables

  • Age
  • Body fat.
Description of Actual Data Sample:

Initial N

96 women, 48 in each group

Attrition (final N)

70 women (73% completion), 35 in each group (equal retention)

Age 

Mean 39.79±6.1 years in Traditional Food Group, 36.7±6.3 years in Meal Replacement Group

Ethnicity 

Not described

Other relevant demographics

Anthropometrics 

Groups were significantly different at baseline in terms of age and body fat (P<0.05)

Location

University of Nevada community 

Summary of Results:

 

Variables Traditional Food Group
Six Months-Baseline
Traditional Food Group
Year 1-Baseline
Meal Replacement Group
Six Months-Baseline
Meal Replacement Group
Year 1-Baseline
Weight (kg) -5.4±5.4 -6.1±6.7 -5.2±4.0  -5.0±4.9 
BMI -2.1±2.2  -2.6±2.9  -1.9±1.4  -1.9±1.9 
Body fat
(percentage)
-5.4±6.5  -5.7±8.1  -4.3±4.0  -4.5±6.5 
Waist circumference
(cm)
-6.1±5.5 -6.1±7.0  -4.8±3.22  -4.9±4.6 
REE (calculated) -52.2±51.1 -75.6±83.0  -46.6±36.4  -50.2±47.1 

  Other Findings

  • There was a mean decrease in the use of meal replacements between assessments: 1.4±0.6 servings per day consumed at six months (range zero to 2.7) and 1.2±0.7 servings per day consumed at 12 months (range zero to two)
  • Weight loss for the study completers was not significantly different between the groups, but was significantly different (P<0.05) within each group with a mean weight loss of -6.1±6.7kg (Traditional Food Group) vs. -5.0±4.9kg (Meal Replacement Group)
  • Both groups had macronutrient ratios that were within the ranges recommended (50% carbohydrate,19% Protein, 31% fat in the Traditional Food Group vs. 55% carbohydrate, 16% Protein, 29% fat in the Meal Replacement Group)
  • Reported reduced energy intake was similar (5,729±1,424kJ in Traditional Food Group vs. 5,993±2,016kJ in the Meal Replacement Group)
  • There was an improved dietary intake pattern in both groups as indicated by decreased intake of saturated fat (less than 10%), cholesterol (less than 200mg per day) and sodium (less than 2,400mg per day), with increased total servings per day of fruits and vegetables (4.0±2.2 in the Traditional Food Group vs. 4.6±3.2 in the Meal Replacement Group).
  • However, the Traditional Food Group had a significantly lower dietary intake of several vitamins and minerals compared to the Meal Replacement Group and was at greater risk for inadequate intake.  

 

Author Conclusion:

In conclusion, the results of this study point to the importance of using an adequately fortified meal replacement product or taking a multivitamin and mineral supplement to ensure nutrient adequacy during reduced energy intake for weight loss.  This advice applies not only to those following a weight loss plan on their own, but also to those following a weight loss plan under professional guidance.

Funding Source:
Industry:
Unilever; Slim-Fast Nutrition Institute
Food Company:
In-Kind support reported by Industry: Yes
Reviewer Comments:

73% drop-out rate. Significant differences between groups at baseline in age and body fat. Subjects were not compliant with the meal replacement intervention. Authors note that the primary measure of diet adequacy was food records kept by subjects, which may have limitations. Physical activity not addressed.

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? ???
  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? ???
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? No
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) ???
  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? 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? ???
  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? Yes
  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.) 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? Yes
  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? ???
  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)? Yes
  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? Yes
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