AWM: Eating Frequency and Patterns (2013)
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.
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.
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.
5,145 participants were recruited from 16 centers in the US.
- 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.
- 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.
Timing of Measurements
The data reviewed is baseline information obtained in a current longitudinal study.
- 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).
- Marital status
- 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)|
|Married or live in (%)||61.7||39.6||61.8||52.2||59.2||85.9||72.5||78.9||70.9||71.4|
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.
- 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).
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.
|Government:||National Institutes of Health grants|
- 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
|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|
|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|