EAL

MNT: Weight Management (2015)

Citation:

Lapointe A, Weisnagel S, Provencher V, Bégin C, Dufour-Bouchard A, Trudeau C, Lemieux S. Comparison of a dietary intervention promoting high intakes of fruits and vegetables with a low-fat approach: long-term effects on dietary intakes, eating behaviours and body weight in postmenopausal women. The British Journal of Nutrition, 2010; 104: 1,080-1,090. PubMed ID: 20482930

Study Design:

Non-Controlled Trial

Class:

D - Click here for explanation of classification scheme.

Quality Rating:

POSITIVE: See Quality Criteria Checklist below.

Research Purpose:

To compare an intervention based on an approach goal (increasing fruit and vegetable intake) with an intervention based on an avoidance goal (decreasing high fatty food intake)
Primary outcome was weight maintenance and secondary outcomes were changes in dietary intake, eating behaviors and metabolic profile between the end of the six-month dietary intervention and one-year follow-up.

Inclusion Criteria:

Obese post-menopausal women
45 years to 68 years of age
BMI of at least 28kg/m²
Waist circumference at least 88cm
Stable body weight (±2.5kg for the last three months before study)
Written informed consent provided.

Exclusion Criteria:

Type 2 diabetes mellitus or other metabolic disorders
Using any type hormone therapy
High level of depressive symptoms or having eating disorders as determined respectively by the Beck Depression Inventory and Eating Disorder Examination Questionnaire, respectively.

Description of Study Protocol:

Recruitment

Recruited through local newspapers in the Quebec City metropolitan area.

Design

Post-menopausal women were randomly assigned to one of two approaches through the use of permuted block randomization: An approach using restrictive messages to limit high-fat foods (LOFAT) or an approach emphasizing non-restrictive messages directed towards the increase of fruit and vegetable intake (HIFV)
The six-month dietary intervention included three group sessions and 10 individual sessions with a dietitian
Dietary intakes, eating behaviors and anthropometrics were measured at baseline, at the end of the dietary intervention and at six months and 12 months after the end of intervention.

Blinding Used
None.

Intervention
Dietary intervention approach.

Statistical Analysis

Anthropometric variables, dietary intakes, eating behaviors and metabolic variables were analyzed according to intention to treat procedure in which baseline values were carried forward for subjects with missing data at time of six, 12 and 18 months
Statistical analysis performed with completes only
Women in the HIFV Group were stratified into three groups, according to the tertile of change in fruit and vegetable intakes between baseline and six months and the LOFAT Group was stratified in a similar manner based on tertile of change in fat intake
PROC MIXED procedure
Significant group-by-time interactions observed were then tested to further depict the main interaction effect
Tukey-Kramer adjustment
Spearman correlations
X² analysis
Power calculation estimated that a sample of 26 subjects per Intervention Group would allow the detection of a 7% difference in body weight at 18 months, with a standard deviation of 10%, a probability of rejecting a null hypothesis of 0.05 and a probability of correctly accepting a true null hypothesis of 0.8.

Data Collection Summary:

Timing of Measurements

Validated food frequency questionnaire (FFQ) administered five times: At screening, at baseline, at the end of the dietary intervention and during follow-up (12 and 18 months)
Anthropometric variables were measured at baseline, six months, 12 months and 18 months
Three-Factor Eating Questionnaire (TFEQ) was completed at baseline, at six months, 12 months and 18 months
Dieting history collected at baseline
Metabolic variables were measured at baseline, six months, 12 months and 18 months
Glucose tolerance test was performed at baseline, six months and 18 months.

Dependent Variables

Weight
Height
Waist circumference
TFEQ scores for dietary restraint, disinhibition and hunger
Dieting history
Metabolic variables: Lipids, lipoproteins
Oral glucose tolerance test to measure insulin sensitivity.

Independent Variables

Dietary intervention.

Control Variables

Height.

Description of Actual Data Sample:

Initial N
68 females.

Attrition (Final N)
56 females.

Age

HIFV: 56.2±4.4 years
LOFAT Group: 58.1±4.6 years
No significant difference in age between groups.

Ethnicity
Not described.

Other Relevant Demographics

Women who withdrew from the study were characterized by more previous dieting attempts, compared with those who completed the study (6.5±3.5 times vs. 4.3±2.8 times, respectively).

Anthropometrics

No significant difference in baseline body weight between groups (85.8±8.9kg in the LOFAT Group and 85±8.9kg in the HIFV Group)
Women who withdrew from the study had similar baseline body weight as compared to those who completed the study.

Location
Quebec City, Canada.

Summary of Results:

Key Findings

Changes in dietary intake
- Fruit and vegetable intake increased significantly at the end of the six-month dietary intervention, compared with baseline in the HIFV Group (P<0.05) and was significantly higher than in the LOFAT Group (P<0.05), however during follow-up intake returned towards baseline values in the HIFV Group and intakes measured at 12 and 18 months were no longer significantly different from baseline intakes
- Energy intake remained constant during the six-month dietary intervention in the HIFV Group and decreased at 12 and 18 months compared with baseline, as was also observed for protein and carbohydrate intakes
- Total fiber intake and weight of food returned towards baseline values at 12 and 18 months, while energy density remained significantly lower compared with baseline in the HIFV Group
- In the LOFAT Group, energy, protein, carbohydrate and fat intake as well as energy density were significantly lower at six months than baseline and remained lower during the follow-up period as compared to baseline.
Changes in body weight and waist circumference
- Weight decreased at six months (LOFAT, -3.8kg; HIFV, -1.8kg; P<0.05), was maintained at 12 months, with slight regression at 18 months (LOFAT, -2.5kg; HIFV, -1.5kg; NS)
- Waist circumference decreased at six months (LOFAT, -4.2cm; HIFV, -2.5cm; P<0.05) with slight regression by 18 months (LOFAT, -3.2cm; HIFV, -2.3cm; NS).
Changes in metabolic variables
- At the end of the six-month intervention, fasting plasma glucose and insulin, as well as blood pressure, were significantly lower than baseline in the LOFAT Group
- Fasting plasma insulin and systolic blood pressure significantly decreased in the HIFV Group
- At 18 months, only fasting insulin remained lower than baseline in both groups, whereas systolic blood pressure remained lower than baseline only in HIFV Group.
Changes in eating behaviors
- At six, 12 and 18 months, dietary restraint and flexible restraint were higher than baseline in the LOFAT Group, whereas no change was observed in the HIFV Group
- Disinhibition remained lower at 18 months compared with baseline in both groups
- Hunger was not significantly different at 18 months in both groups, but external locus of hunger was significantly lower at 18 months than baseline in the HIFV Group
- No significant associations between change in body weight and change in eating behaviors were noted in the LOFAT Group
- In the HIFV Group, changes in dietary restraint and flexible restraint were both negatively associated with change in body weight (R=-0.52 and R=-0.42, respectively; P<0.05), while change in hunger was positively associated with change in body weight (R=0.38; P=0.049).

Variables	Time	LOFAT Group	HIFV Group	Difference Between Groups
Energy intake (kJ)	Baseline	10,288±2,703	9,205±2,389	Time: <0.001 Group: 0.196 Time x group: 0.01
	Six months	8,121±2,117^a	8,644±2,113
	12 months	8,360±2,125^a	8,368±2,092^a
	18 months	8,586±2,473^a	8,259±2,443^a
Total fat intake (grams)	Baseline	101.5±40.1	83.8±29.2	Time: <0.001 Group: 0.234 Time x group: 0.014
	Six months	72±27^a	74.4±25.4
	12 months	78.1±28.5^a	75±23.3
	18 months	80.9±31.4^a	75.5±28.7
Total fiber intake (grams)	Baseline	23.8±5.6	23.6±6.2	Time: 0.006 Group: 0.049 Time x group: 0.033
	Six months	23.5±6.2	26.7±5.1^a,c
	12 months	21.8±5.2	23.9±5.8^b
	18 months	23±6.8	23.5±7.1^c
Energy density (kJ/g)	Baseline	7.0±1.1	6.5±1.1	Time: <0.001 Group: 0.0468 Time x group: 0.594
	Six months	5.9±0.9^a	5.5±1.1^a
	12 months	6.2±1.0^a	6.0±1.2^a
	18 months	6.3±0.8^a,^b	6.0±1.2^a
Weight of food (grams)	Baseline	1,278±294	1,262±318	Time: 0.012 Group: 0.0141 Time x group: 0.001
	Six months	1,190±291	1,398±285^a,^c
	12 months	1,178±278	1,252±283^b
	18 months	1,187±288	1227±351^b
Dietary restraint	Baseline	8.2±4.6	9.6±4.0	Time: 0.001 Group: 0.015 Time x group: 0.002
	Six months	12.5±4.3^a	11±4.5^c
	12 months	10.8±4.3^a	10.2±4.6
	18 months	11±4.4^a	10.7±4.7
Flexible restraint	Baseline	2.5±1.7	3.1±1.7	Time: <0.001 Group: 0.004 Time x group: 0.002
	Six months	4.2±2.0^a	3.3±1.8^c
	12 months	3.7±1.8^a	3.3±1.7
	18 months	3.7±1.7^a	3.5±1.7
Rigid restraint	Baseline	2.8±1.9	3.3±1.6	Time: 0.004 Group: 0.219 Time x group: 0.483
	Six months	3.4±1.8	3.5±1.8
	12 months	3.0±1.9	3.2±1.9
	18 months	3.4±1.8	3.3±2.1
Disinhibition	Baseline	8.7±3.3	9.8±3.1	Time: 0.001 Group: 0.472 Time x group: 0.218
	Six months	6.9±3.1	7.8±3.1^a
	12 months	6.9±2.9^a	7.2±3.0^a
	18 months	7.1±2.9^a	7.0±2.9^a
Hunger	Baseline	5.6±3.5	6.9±3.8	Time: <0.001 Group: 0.929 Time x group: 0.865
	Six months	3.9±3.4^a	4.9±3.8^a
	12 months	3.8±3.7^a	4.9±3.7^a
	18 months	4.6±3.6	5.5±4.0
Internal locus to hunger	Baseline	1.8±1.9	2.9±2.4	Time: <0.001 Group: 0.451 Time x group: 0.207
	Six months	1.4±1.7	1.8±2.2^a
	12 months	1.2±1.8	1.7±2.2^a
	18 months	1.7±2.0	2.1±2.1
External locus to hunger	Baseline	2.5±1.3	3.3±1.4	Time: <0.001 Group: 0.933 Time x group: 0.542
	Six months	1.6±1.6^a	2.4±1.7^a
	12 months	1.7±1.4^a	2.4±1.7^a
	18 months	2.1±1.5	2.3±1.3^a

^a Mean value significantly different from baseline (P<0.05)
^b Mean value significantly different from that at six months (P<0.05)
^c Mean value significantly different from that of the LOFAT Group (P<0.05).

Author Conclusion:

A six-month dietary intervention restricting high-fat foods was successful in maintaining food habits, while the adherence to a six-month dietary intervention promoting high intake of fruits and vegetables was difficult to maintain. It was difficult to determine which of the two approaches was more successful in terms of weight maintenance since no significant difference in weight loss at 18 months was found between the two in intervention groups.

Funding Source:

Not-for-profit

Canadian Diabetes Association

Reviewer Comments:

Limitations included small sample size and lack of control 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)	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.)	No
	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?		Yes
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	Yes
	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?	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?		Yes
	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?	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?	Yes
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	Yes
	6.6.	Were extra or unplanned treatments described?	Yes
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	Yes
	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)?	No
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	No
	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?	Yes
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