AWM: Eating Frequency and Patterns (2013)

Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

To examine breakfast consumption in subjects maintaining a weight loss in the National Weight Control Registry (NWCR).

Inclusion Criteria:

For inclusion in the NWCR:

  • > 18 years old
  • having lost > 13.6 kg (30 lb)
  • maintained the weight loss for > 1 year
Exclusion Criteria:
None stated.
Description of Study Protocol:

Recruitment Not stated.

Design Cross-sectional - used data gathered at initial enrollment in the NWCR.

Blinding used (if applicable) NA

Intervention (if applicable) NA

Statistical Analysis Results are presented as mean ± SD or as frequencies.  Subject characteristics were compared for men and women using independent sample t tests for continuous variables and Chi-square for frequencies. Although the authors do not state so in the statistical analysis section, other t-tests appear to have been conducted with breakfast consumption (yes/no) being the grouping variable.

Data Collection Summary:

Timing of Measurements Taken at enrollment in the NWCR.

This was a descriptive study that only performed statistical analyses to look for gender differences.  Variables used to describe successful maintainers of weight loss: 

  • nutrient intake (assessed by the Block FFQ)
  • physical activity (assess with the Paffenbarger Physical Activity Questionnaire)
  • current and maximum BMI (self-report)
  • duration of weight loss
  • age
  • gender
  • education level
  • marital status
  • breakfast consumption patterns assessed by:
    • initially, asking how many days of a 7-day week respondents typically ate breakfast
    • later (for 1895 of the 2959 subjects) subjects were asked a series of questions pertaining to breakfast:
      • if they had eaten breakfast in the last 3 months
      • if yes, how often they ate a hot or cold cereal for breakfast (1=always to 4=rarely or never) 
      • how often they ate fruit for breakfast (1 to 4 again)
Description of Actual Data Sample:

Initial N: 2350 women, 607 men, 2 did not report gender

Attrition (final N): 2953

Age: Women - 44.8±12.0 years; men - 51.8 ±13.2 years.

Ethnicity: 95% white

Other relevant demographics: 64% were married, education level was not reported.

Anthropometrics Not reported. BMI was reported but betwen group differences (men and women) were not reported.

Location: U.S.

Summary of Results:
  • almost 90% reported eating breakfast > 4 days/week, with 78.3% of the respondents (2313) reporting eating breakfast every day
  • 3.9% reported never eating breakfast
  • slightly more men than women reported not eating breakfast (7.6 vs. 4.6%, p = 0.017)

Of the breakfast eaters:

  • 29.6% (530) always eat cereal
  • 30.1% (540) usually/often eat cereal
  • 20.6% (369) sometimes eat cereal
  • 19.7% (354)  rarely/never consumed cereal
  • 31.4% (564) always eat fruit
  • 24.2% (435) usually/often eat fruit
  • 23.6% (423) sometimes eat fruit
  • 20.8% (373) rarely/never consumed fruit

Differences between breakfast eaters (> 4 times/week, n=2645)) and non-eaters (<3 times/week, n=314):

  • no difference in weight lost (34 vs. 32 kg, p=0.14)
  • no difference in duration of weight loss maintenance (7.7 vs. 7.9 years, p=0.29)
  • no difference in energy intake (1394 kcals/day for breakfast eaters vs 1366 kcals/day for non-breakfast eaters, p=0.50)
  • more (p=0.05) physical activity in breakfast eaters (2657 vs 2391 kcal/week)
  • mean age (44.9±10.4 years) for subjects who did not report eating breakfast was slightly lower than the group who reported eating breakfast (47.4±13.0 year, p=0.017)
Author Conclusion:

The authors conclude that eating breakfast should be added to the behaviors that are common to successful weight-loss maintainers and cite the high proportion of breakfast eaters in the NWCR who report eating breakast every day as as confirmation of this.  They also postulate several reasons why regular breakfast consumption may be useful in maintaining weight loss: reducing hunger that could lead to overeating later in the day, choices of less energy-dense food during the remainder of the day, and eating breakfast may enable subjects to perform physical activity.

Funding Source:
Government: NIH
General Mills
Food Company:
Reviewer Comments:
This is an interesting study from a good data base of people able to maintain weight loss for an extended period of time. Although these findings add to our knowledge, both about the value of eating breakfast and the behaviors associated with maintenance of weight loss, the value of the study is decreased due to the descriptive nature and the lack of a comparison group.
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) No
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? N/A
  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? N/A
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  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? 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? 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? N/A
  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? 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? N/A
  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? No
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