DM: Effectiveness of MNT Provided by RD/RDN (2015)

Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To investigate the effectiveness of intensive innovative methods for implementing isocaloric dietary prescriptions on weight management and glycemic control in overweight men with type 2 diabetes after 12 weeks and to determine if the implementation method resulted in maintaining these improvements.
Inclusion Criteria:
  • Male
  • Type II diabetes
  • Treated with oral hypoglycemic agents or by diet alone
  • Under 70 years of age
  • BMI between 25 and 40kg per m2.
Exclusion Criteria:
  • Active thyroid disease
  • Active psychiatric disease
  • Unstable angina
  • Elevated urate levels
  • Autonomic neuropathy
  • Impaired renal function
  • Using medication such as lithium, anticonvulsants, or antipsychotic drugs.
Description of Study Protocol:
  • Recruitment: Subjects were recruited by newspaper advertisements

  • Design: RCT

  • Blinding used: Not possible; lab tests.


12-week intervention period. Subjects were randomized into one of three groups:

  1. Intermittent energy restriction (IER)
  2. Pre-portioned meals (PPM)
  3. Self-selected meals (SSM).

All diets were isocaloric, averaging 1,400kcal to 1,700kcal per day. Subjects were seen by a dietitian and physician weekly. 18 months after the intervention period, subjects were contacted for follow-up visit, where outcomes were measured. Subjects were not informed of the 18-month follow-up at the start of the study.

Statistical Analysis

  • Data was presented in means±SD for continuous variables and counts (percentages) for categorical variables

  • Analyses were carried out in intent-to-treat

  • Significance was set at P<0.05.

Data Collection Summary:
  • Timing of measurements: Baseline, 12 weeks, 18 months.

Dependent Variables

  • Weight (kg)
  • Waist circumference (cm) 
  • Body fat (percentage)
  • HbA1C (percentage)
  • Triglyceride levels (mmol per L).

Independent Variables

  • Diet groups:
    1. Intermittent energy restriction (IER)
    2. Pre-portioned meals (PPM)
    3. Self-selected meals (SSM).
Description of Actual Data Sample:
  • Initial N: 51 men
  • Attrition (final N): 27 men (52.9%) attended follow-up at 18 months
  • Age: Mean, 54 years
  • Ethnicity: Not given
  • Anthropometrics: Mean BMI: 31.7 kg/m2
  • Location: Queensland, Australia.
Summary of Results:


Baseline (N)

12 Weeks (N)


18 Months (N)


Weight (kg)

98.5±12.3 (51)

92.1±11.4 (51)


96.7±12.1 (27)


Waist Circumference (cm)

110.7±9.5 (51)

102.7±9.6 (50)


108.6±9.7 (27)


Body Fat (percentage)

26.4±4.0 (49)

25.0±4.2 (38)


26.3±3.5 (27)

HbA1C 7.9±2.0 (50) 6.7±1.5 (39) P<0.001 8.3±2.3 (27) P=0.749
Triglyceride levels (mmol/L) 1.8±0.9 (49) 1.5±0.7 (37) P=0.02 2.2±1.2 (27) *

Other Findings

  • Loss to follow-up was not different between the diet groups (P=0.94)
  • There was no significant difference between diet groups for changes in all clinical outcome measures after 12 weeks' intervention, except body composition or for changes in outcomes after 18 months
  • Of the 27 subjects at 18 months' follow-up, four were weight-stable (not more than one kg weight loss or gain) and 23 regained weight (more than one kg weight gain)
  • After the 12-week intervention, subjects in the PPM group had a significantly greater reduction in body fat percentage, compared to subjects in the SSM group (P=0.009), but it was not significantly different from the IER group (P=0.406)
  • A significant mean reduction in energy intake of 564±665kcal per day was evident after 12 weeks of dietetic intervention, compared to energy intake prior to dietary stabilization (P<0.001)
  • At follow-up, subjects' energy intake had significantly increased since the end of the intervention (P<0.001)
*Total cholesterol and LDL cholesterol did not differ significantly from baseline either at the end of intervention or at the 18-month follow-up. HDL cholesterol was not significantly different from baseline after the intervention, but significantly increased by 0.15±0.18 mmol per L at follow-up.
Author Conclusion:
  • A dietary prescription of 1,400kcal to 1,700kcal per day was effective in achieving a 6% weight loss and improving glycemic control
  • The method of implementation made no difference to the outcomes between groups at 12 weeks or 18 months
  • It was the intensive weekly contact with a health professional, in combination with moderate energy restriction, that facilitated the success of the short-term results.
Funding Source:
Government: National Office of Overseas Skills Recognition
Reviewer Comments:

Study intervention was interesting, however only 53% of subjects were seen at the 18-month follow-up.

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) No
  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? 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? No
  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? N/A
  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)? Yes
  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? 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