• Increase Font Size
  • Decrease Font Size
  • View as PDF

AWM: Eating Frequency and Patterns (2013)

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

To describe the intentional weight loss strategies in a diverse sample of overweight participants with type 2 diabetes enrolled in the Look AHEAD (Action for Health in Diabetes) clinical trial.

Inclusion Criteria:

Sample population drawn from the Look AHEAD study, a multicenter (16 US locations), randomized clinical trial of overweight and obese adults (aged 45 to 74 years) with type 2 diabetes and body mass index (BMI) of 25kg/m2 or more.

Exclusion Criteria:

Persons with inadequate diabetes control (A1C higher than 11%) or with underlying diseases likely to limit life span or affect the safety of losing weight.

Description of Study Protocol:

Recruitment

5,145 participants were recruited from 16 centers in the US.

Design

  • Cross-sectional analysis of reported weight loss strategies at baseline of entering the study
  • The Look AHEAD trial will compare the long-term (11.5 years) effects of an intensive lifestyle intervention for weight loss on incidence of serious cardiovascular events with those of a diabetes support and education control condition.

Statistical Analysis

  • To describe weight loss strategies used by this sample, T-tests, ANOVAs and chi-square tests were used to assess for differences between sex and race/ethnicities in all variables
  • The relationships between BMI and minimum number of intentional weight losses of more than 5-lb and minimum total amount of intentional weight loss were examined in univariate regression models to establish their need to be included in the larger multivariate model for BMI
  • Variables significantly related to BMI were identified and a correlation matrix was conducted.
Data Collection Summary:

Timing of Measurements

The data reviewed is baseline information obtained in a current longitudinal study.

Dependent Variables

BMI.

Independent Variables

  • Intentional weight loss history (reported frequency)
  • Self weighing frequency (incidence per week)
  • Eating patterns (number of meals per week including fast food meals)
  • Weight control practices (reported behaviors).

Control Variables

  • Sex
  • Age
  • Race
  • Marital status
  • Education
  • Income.
Description of Actual Data Sample:
  • Initial and final N: 5,145 participants (59.5% female; N=3,063, male, N=2,082)
  • Age: 58.7±6.8 years
  • Ethnicity, relevant demographics and anthropometrics:
  F, N-H White F, N-H Black F, Hispanic F, NA F, Other M, N-H White M, N-H Black M, Hispanic M, NA M, Other
N (%) 1,665 (54.4) 614 (20.1) 483 (15.8) 203 (6.6) 98 (3.2) 1,581 (75.9) 189 (9.1) 194 (9.3) 55 (2.6) 63 (3.0)
BMI (kg/m2) 36.7±6.2 36.8±6.0 35.5±5.7 36.3±6.5 35.7±6.3 35.3±5.5 35.5±5.5 34.7±5.2 33.4±5.2 33.5±5.1 
Married or live in (%) 61.7 39.6 61.8 52.2 59.2 85.9 72.5 78.9 70.9 71.4
Employed (%) 67.4 68.3 54.0 63.8 75.8 82.2 78.6 74.5 69.8 75.5

F = Female, M = Male, N-H = Non- Hispanic, NA = Native American.

Education, family income and more specific age information is provided in the study, but not reported here.

  • Location: 16 locations in US. 
Summary of Results:

Key Findings

  • 88.9% of women and 86.2% of men reported at least one previous intentional weight loss of five or more pounds
    • Native American women had the lowest incidence (66.5%)
    • Non-Hispanic women had the highest incidence (96.2%)
  • 41.4% of all participants reported self-weighing at least weekly. Those that self-weighed weekly had a lower BMI (35.3±5.6kg/m2, P<0.001) than those that weighed themselves less than once per month
  • Breakfast was eaten 6.0±1.8 days per week and 5.0±3.1 meals and snacks were eaten per day
    • Participants who consumed breakfast seven days per week had a lower BMI (35.6±5.7kg/m2, P<0.0001) than those who ate breakfast three to six days per week
    • Women consumed more meals and snacks per day than men (5.1±3.2 vs. 4.8±2.9; P<0.001), with no differences in race/ethnicity for meals and snacks consumed per day
  • Participants reported consuming 1.9±2.7 fast food meals per week
  • Weight control practices commonly reported included:
    • Increasing fruit and vegetable intake
    • Cut out sweets and junk food
    • Eat less high-carbohydrate foods
    • Increasing exercise
    • Decreasing fat intake
    • Reducing calories
  • More intentional weight loss attempts and greater weight loss were associated with a higher BMI (P>0.0001)
  • Adjusted models showed that self-weighing less than once per week (B=0.83), more fast food meals consumed per week (B=0.14) and fewer breakfast meals consumed per week (B=-0.19) were associated (P<0.05) with a higher BMI (R2=0.24).
Author Conclusion:

Several weight loss strategies (weekly self-weighing, regular consumption of breakfast and reduced intake of fast food) were associated with lower BMI in overweight individuals with type 2 diabetes.

Funding Source:
Government: National Institutes of Health grants
Reviewer Comments:
  • Strengths: Large, ethnically and socio-economically diverse sample with objectively measured height and weight
  • Weaknesses: Baseline data is self-reported.
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) N/A
  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) N/A
 
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) N/A
  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? 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? Yes
  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? N/A
  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? N/A
  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? N/A
  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? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes