Adult Weight Management

AWM: Eating Frequency and Patterns (2013)

Citation:

Malinauskas BM, Raedeke TD, Aeby VG, Smith JL, Dallas MB. Dieting practices, weight perceptions and body composition: A comparison of normal weight, overweight and obese college females. Nutr J 2006; 5: 11.

PubMed ID: 16579846
 
Study Design:
Cross-Sectional Study
Class:
D - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To determine differences in dieting practices, weight perceptions and body composition of normal weight, overweight and obese female college students.

Inclusion Criteria:

Students from five introductory nutrition courses taught by two instructors and invited to participate during the spring semester of 2005.

Exclusion Criteria:

Males and females greater than 24 years of age and females reporting current pregnancy were excluded from analysis.

Description of Study Protocol:

Recruitment

A scripted description of the study (read by the instructor at the beginning at a class period which highlighted the study protocol) and an electronic course announcement posted on Blackboard were the means used to inform students about the study. Extra credit was available to students who completed the study.

Design

A cross-sectional study with data collected on two occasions. During the first meeting, students completed a survey regarding dieting practices, weight perceptions and level of physical activity participation. During the second meeting, body composition assessments were completed.

Blinding used

Implied with measurements

Intervention

Not applicable 

Statistical Analysis

  • Descriptive statistics included means, standard deviation and frequency
  • Subsequent data analysis involved Pearson X2  and one-way analysis of variance with comparison for all pairs that were significantly different using Tukey-Kramer honestly significant difference test
  • A significance level of 0.05 was used for statistical analysis.
Data Collection Summary:

Timing of Measurements

Spring 2005

Dependent Variables

Diet practices questionnaire including:

  • Demographics
  • Dieting practices  
  • Weight perception
  • Perceived sources of pressure to be a certain weight
  • Thirty day physical activity recall.

Independent Variables

Weight status:

  • Normal weight
  • Overweight
  • Obese based on body mass index (BMI).

Control Variables

  • Age
  • Height
  • Weight
  • BMI
  • Body fat percentage
  • Waist-to-hip ratio
Description of Actual Data Sample:
  • Initial N: 230 females
  • Attrition (final N): 185
  • Age: Mean age of participants was 19.7 years
  • Ethnicity: 
    • White 78%
    • Black 18%
    • American Indian, Asian or Hispanic 4%
  • Other relevant demographics: 70% were freshman and sophomores
  • Anthropometrics: BMI Range n:
    • Normal weight: BMI 18.5 to 24.9kg/m2; n=113
    • Overweight:  BMI 25 to 29.9kg/m2; n=35
    • Obese:  BMI 30kg/m2 or greater; n=21
  • LocationGreenville, North Carolina, USA.

 

Summary of Results:

Key Findings

Question One: Body Composition, Weight Perceptions and Physical Activity of Normal Weight, Overweight and Obese Groups

  • Despite the following significant differences (P<0.01) among the groups for:
    • Weight; F(2,166)=171
    • BMI; F(2,166)=272
    • Body fat; F(2,166)=96
    • Waist-to-hip ratio; F(2,166)=53
  • Mean physical activity was similar among the groups, F(2,165)=0.5, P=0.61
  • Significant differences were found among groups for perceived healthy weight, F(2,163)=76, P<0.01 and attractive weight, F(2,160)=74, P<0.01 compared to current weight. 
  • Mean perceived healthy weight and attractive weight were lower than current weight as follows:
  Healthy Weight Attractive Weight
Normal Weight 5% 6%
Overweight 13% 15%
Obese 23% 26%
  • All groups perceived natural weight to be greater than current weight, meaning if no attempt was made to control weight then weight would be 2% to 6% greater than current weight 
  • The majority (80%) of participants reported using physical activity to control their weight. However, 32% did not participate regularly programmed recreation, sport or heavy physical activity. Overall, only 19% of participants reported spending over three hours per week in vigorous aerobic activity:
    • Normal weight 21%
    • Overweight 21%
    • Obese 5%.

Question Two: Identifying Perceived Sources of Pressure To Be A Certain Weight Among These Groups

  • 80=3% of participants reported ever consciously trying to lose or control their weight, including 80% of normal weight, 91% of overweight and 86% of obese participants
  • Mean age when dieting was initiated was 15.7 years (SD=2.3) which was similar among groups, F(2,137)=1, P=0.3
  • 58% percent of participants reported pressure to be a certain weight; primary sources were self (54%), media (37%) and friends (32%).

Question Three:  Identifying Weight Loss Behaviors Ever Used To Consciously Lose Or Control Weight Among Groups

  • Dieting behaviors were assessed to determine if use differed among normal weight, overweight and obese participants
  • The five most common behaviors used by all of the participants were:
    • Exercising 80%
    • Eating or drinking  low fat or fat free versions of foods or drinks 59%
    • Consciously eat less than you want 51%
    • Eating or drinking sugar free versions of foods or drinks 43%
    • Counting calories 40%
  • Eating less than you want (P<0.01) and use of artificial sweeteners (P<0.04) were the only behaviors for which frequency of use were the only behaviors for which frequency of use was significantly different among groups
  • Other behaviors with low frequency of use were:
  Normal Weight Overweight Obese
Not eating foods with  high glycemic index 4% 6% 0%
Smoking cigarettes 8% 14% 5%
Using laxatives after eating 2% 6% 5%
Vomiting after eating 4% 6% 5%
Skipping lunch 10% 9% 10%
Skipping dinner 4% 9% 10%

Question Four:  Identifying The Most Prevalent Weight Control Products and Commercial Diets Used By Female College Students

  • Weight control products used by participants included:
    • Over-the-counter meal replacement drinks 35%
    • Supplements 26%
    • Meal replacement bars 18%
    • Dieter's green tea, green tea and green tea pills 11%
    • Chromium picolinate 3%
    • Physician prescribed weight loss pills 3%
  • The most popular commercial diets used by participants were:
    • Atkins or South Beach 20%
    • Weight Watchers 11%
    • Subway, Sugar Guster, The Zone 7%. 
Author Conclusion:

The purpose of this study was to investigate dieting practices, weight perceptions and body composition among normal weight, overweight and obese college females. Findings from this study support the general belief that dieting by college females is a common weight management strategy. These findings suggest that health educators should promote education and intervention strategies for females that encourage appropriate weight control practices and dispel unhealthy and ineffective weight loss myths (using laxatives and skipping breakfast are effective weight control methods). 

Implications from this study are numerous. Female college students, regardless of weight status would benefit from open discussions with health educators to identify healthy and unhealthy dieting practices they use. Throughout these discussions, females could identify healthy dieting practices that could be expanded upon to promote a healthy weight status and recognize the health consequences associated with using unhealthy dieting practices.

Because this study involved only female college students at a state university, the implications discussed here are subject to replication with other participants, researchers can consider how to effectively target specific dieting practices among females to promote healthy eating and exercise to promote and maintain a healthy weight. Future research should identify which dieting practices dieters report most content with and believe are most successful to promote short- and long-term weight management.

Funding Source:
University/Hospital: Undergraduate Research Assistantships, East Carolina University Honors Program
Reviewer Comments:

The authors note the following limitation:

Since the study was a cross-sectional design, it was not known if there was a causal relationship between dieting and weight control. Longitudinal studies would be the best way to measure if dieting frequency among females and methods of dieting choices change throughout the lifespan and if there exists a causal relationship between dieting and weight control.

They also note that the study is subject to replication of the results, since only female college students in a state university were studied. This is not likely a representative sample of the relevant population.

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? No
  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? No
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.) 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.) Yes
  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.) 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