EAL

AWM: Portion Control (2006)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To examine the effectiveness and efficacy of a short-term behavioral strategy to target a fequently endorsed problematic behavior of post-dinner snacking.

Inclusion Criteria:

BMI > 25
18-65 years of age
not endorsing a weight change > 15 lb over the past 6 months
endorsing a 4 or 5 on the questions "To what extent does snacking after dinner contribute to your weight problem?", which was scaled from 1 "not at all' to 5 "to a very large extent"

Exclusion Criteria:

being pregnant, lactating, or trying to conceive
having significant cardiac disease, uncontrolled diabetes, or hypertension
active bulimia nervosa, binge eating disorder, or anorexia nervosa
presence of alcohol or substance abuse
history of infectious diseases
aversion or sensitivity to gluten or cereal products
presence of any condition for which weight loss or caloric restriction would be contraindicated

Description of Study Protocol:

Recruitment Participants responded to a study announcement.

Design RCT - potential subjects were screened via telphone and, if they met inclusionary criteria, they were invited to attend an introductory session where they were screened for exclusionary criteria. The resulting participants who agreed to participate were randomly assigned to cereal (CR) or no cereal (NC) groups. The CR group was instructed to eat 1 cup of ready-to-eat cereal along with 2/3 cup of low fat milk at least 90 minutes after dinner. A selection of cereals was provided by the Kellogg Co. Milk-intolerant individuals were instructed to use low fat soymilk. The NC group was instructed to continue their normal diet. Follow-up visits were on weeks 2 and 4, after the baseline visit. 3-day dietary recalls (which actually seem to be diet records) were completed by both groups at baseline and at weeks 2 and 4. Each recall consisted of 2 weekdays and 1 weekend day.

Blinding used (if applicable) NA

Intervention assignment to consuming cereal > 90 minutes after dinner or continuing to consume usual intake was done with a random numbers table.

Statistical Analysis correlations, paired and independent t-tests. researchers determined a priori that it was possible to detect a significant difference between groups with 85% probablility for their sample size.

Data Collection Summary:

Timing of Measurements 0, 2, and 4 weeks

Dependent Variables

weight change
change in total intake
change in post-dinner intake - defined as calories consumed in the form of snacks eaten after dinner.

Independent Variables

cereal consumption post-dinner - with compliance consdered to be the self-report of cereal consumption 5 of 7 days.

Control Variables

none reported

Description of Actual Data Sample:

Initial N: 84

Attrition (final N): 58 (22 elected not to participate, 1 woman dropped out of NC group and 3 women dropped out of CR group).

Age: CR:=51.55 +/- 7.91; NC = 48.31 +/- 12.29 year (NS)

Ethnicity: not reported

Other relevant demographics: none reported

Anthropometrics BMI: CR=36.35 +/- 8.10; NC = 34.38 +/- 6.99. At baseline there were no significant differences between groups for age, body weight, BMI, daily energy intake or evening energy intake.

Location: Michigan

Summary of Results:

Effect of Compliance

As compliance (# of days cereal was consumed) increased so did the amount of weight lost (r=-0.36, P=0.057)

Changes in weight

There were no significant weight changes for the total sample.
There was a difference (P<0.05) between weight change in the compliant CR group (n=23) and the total CR group (n=29; -1.85 vs -1.17 lbs.)

Changes in total daily calories

There was a difference in change in total daily calories between the compliant CR group (n=17) and the total CR group (n=14); -293.13 vs. -396.50).

Changes in post-dinner calories

There was a difference (P=0.042) in the compliant CR group and the NC group in post-dinner calories (-103.61 vs. -141.74 kcals).

NOTE: sample sizes differ because of non-compliance on the 3-day recalls.

Author Conclusion:

Eating ready-to eat cereal after the evening meal may attenuate caloric intake in night snackers and promote weight loss in compliant individuals. The presence of a dose-reponse relationship between the number of days of post-dinner cereal consumption and subsequent weight loss provides strong support for the effect of the intervention.

Funding Source:

Industry:

Kellogg Company

Food Company:

Reviewer Comments:

This was a simple but well-done study that provides information regarding the effectiveness of shifting after dinner consumption to a healthier alternative. Although the study had problems with compliance in completing some of the measures (e.g., 3 day diet recalls 3 times) it does provide useful information. As the authors point out, their intervention is simple and may be easier for obese patients to comply with. Even though weight loss in the compliant CR group was modest at -1.85 lbs. over 4 weeks, the intervention was minimal and may prove beneficial over a longer period of time. This study provides a simple, yet apparently effective, strategy for decreasing weight slowly.

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?		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?	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?		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?	Yes
	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?	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?	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?	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)?	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?	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