AWM: Eating Frequency and Patterns (2013)

Study Design:
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Quality Rating:
Research Purpose:

To study the relationship between skipping meals and consuming alcohol and weight loss outcomes among overweight and obese individuals in a weight loss program.

Inclusion Criteria:
  • BMI 27kg/m2 or more
  • Non-smokers.
Exclusion Criteria:

Subjects with musculoskeletal issues that prevented moderate physical activity, cardiovascular disease and insulin-dependent diabetes.

Description of Study Protocol:


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The LEARN weight loss program with verbal and written instructions on self-monitoring of diet and exercise.

Statistical Analysis

  • Chi-square analysis and analysis of variance were used to study differences in demographics and dietary variables between subjects who completed and did not complete the first phase
  • Hierarchical (multi-level) regression was used to study relationships between daily intake and weight loss treatment outcomes. The equations of this analysis were defined using HLM 6.02 software, using restricted maximum likelihood computations.
  • Within-subject variables were person-centered. Variables for between-subject analyses were grand-mean centered to allow for interpretation of subjects relative to the group as a whole.
  • Baseline BMI and group assignment were controlled in all analyses.


Data Collection Summary:

Timing of Measurements

  • Phase one compared two 14-week groups [self-help (SH) group and therapist-assisted self-help (TASH) group]. Both groups of subjects tracked energy expenditure, used the LEARN program, and recorded diet and exercise. The latter group had two 45-minute face-to-face sessions, with weekly 15- to 20-minute telephone calls from the counselor. The weekly calls covered progress, challenges and future goals. 
  • Short phone calls were made or e-mail reminders were sent to SH subjects who stopped self-monitoring during the first phase
  • To promote compliance with self-monitoring, subjects received a ticket toward a random biweekly for $20 when the form was completed
  • Every subject had a weight loss goal of 5% during the first phase. Subjects who did not reach this goal were assigned to an additional three-month group-based weight loss session.
  • Subjects who maintained 5% weight loss for six or more weeks were assigned to weight maintenance intervention
  • This study used only phase one data, which was the first 14 weeks.

Dependent Variables

  • Weight loss:
    • The LEARN program was used, which focuses on gradual weight loss, physical activity and lifestyle changes
    • A 500kcal-per-day deficit was prescribed
  • Energy intake:
    • This was reported from self-monitoring in which subjects were educated on food portion sizes
    • Nutrition guides or online programs helped to estimate energy intake
  • Energy expenditure: Measured using Caltrac accelerometry
  • Exercise duration: Daily, self-reported activities were submitted
  • Body weight:
    • Weekly weights were obtained from subjects' personal scales
    • Consistent weigh-in time was encouraged
    • The researchers measured baseline and post-treatment weights on a digital scale.

Independent Variables

Meal skipping and alcohol consumption:

  • Measured using self-monitoring reports
  • HLM equation was used to assess relationships between skipping meals and weight loss outcome.
Description of Actual Data Sample:
  • Initial N: 54
  • Attrition (final N): 44
  • Age: Mean 46.2 years
  • Ethnicity: 94% Caucasian
  • Other relevant demographics:
    • 74% female
    • 50% with an income of more $30,000 per year
    • 46% had at least a baccalaureate degree
    • 88% had full-time employment
  • Anthropometrics:
    • Mean baseline body mass index was 35.6 (SD=7.3, range 27.5 to 64.8)
    • Mean weight was 99.3kg (SD=24.0, range 67 to 194)
  • Location: Bowling Green State University, Bowling Green, OH.
Summary of Results:

Key Findings

  • Skipping breakfast:
    • The frequency with which subjects did or did not eat breakfast did not affect weekly weight loss for between-subject or within-subject measurements
    • When a subject did not eat breakfast, significantly less energy was consumed compared to days on which was breakfast was eaten (P<0.03)
    • Additionally, on days when breakfast was not consumed, overall energy expenditure was lower (P<0.02) and exercise duration was shorter (P<0.01) than on days when breakfast was eaten
    • Between-subject association was not noted between skipping breakfast and energy expenditure or exercise duration
  •  Skipping lunch or dinner:
    • Frequency of skipping other meals was not associated with weight loss for between-subject or within-subject measurements
    • For days on which dinner was skipped, significantly less energy was consumed compared to days on which this meal was eaten (P<0.01)
    • When lunch was eaten more regularly, the overall energy intake was significantly greater for between-subject association (P<0.01)
    • No within-subject association was noted between frequency of eating lunch and greater energy intake, nor was there between-subject association for eating dinner and daily energy intake
    • Significant between-subject association was found in subjects who ate lunch and resulted in greater energy expenditure (P<0.01) and longer exercise duration (P<0.01)
    • No within-subject association was noted between eating lunch or dinner and daily energy expenditure or exercise duration
  • Alcohol intake:
    • Frequency with which alcohol was or was not consumed did not affect weight loss for between-subject or within-subject measurements
    • For daily energy intake for within-subject analyses when alcohol was not consumed, significantly less energy intake was noted than when alcohol was not consumed (P<0.01)
    • For days when subjects consumed alcohol, exercise duration was longer than on days when alcohol was not consumed (P<0.05)
    • Greater energy expenditure was noted with frequent alcohol intake (P<0.04).


Author Conclusion:

Meal patterns were associated with energy intake. Skipping meals and consuming alcohol did not appear to be associated with weight loss. For weight loss, individuals may want to focus on energy expenditure being greater than energy intake rather than focus on the eating pattern.

Funding Source:
University/Hospital: Department of Psychology, Bowling Green State University, Bowling Green, OH
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) ???
  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%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? Yes
  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.) 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? 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? Yes
  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)? ???
  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? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes