AWM: Very Low Calorie Diets (2007)

Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

To complete 5-year follow-up of an intensive weight loss program in established type 2 diabetic subjects.

Inclusion Criteria:
  • BMI > 30
  • Type 2 diabetes
Exclusion Criteria:

None specifically mentioned - published in prior article.

Description of Study Protocol:


Recruited from hospital clinics and general practice.


Cohort Study.

Blinding used (if applicable)

Not applicable.

Intervention (if applicable)

Group 1 selected VLCD for 6 weeks (650 kcal/day), Group 2 selected LCD and exercise, and 15 followed neither program.  Group sessions of 8 - 15 subjects continued weekly for 6 months then monthly for 12 months.

Statistical Analysis

Results within wach group were analyzed by paired t test and for serum triglyceride levels and psychological well-being by Wilcoxon two sample rank tests.

Data Collection Summary:

Timing of Measurements

Body weight, waist/hip ratio, blood pressure, serum biochemistry, and psychological well being questionnaire results at baseline, 3, 6, 12, 36 and 60 months.  Annual measurements of quality of life, BMI, waist/hip ratio, blood pressure, fasting blood glucose, serum fructosamine and serum lipids.

Dependent Variables

  • Quality of life assessed by Psychological General Well-Being scale
  • BMI
  • Waist hip ratio
  • Blood pressure
  • Blood samples for blood glucose, serum fructosamine and serum lipids 

Independent Variables

  • Group 1 selected VLCD for 6 weeks (650 kcal/day), Group 2 selected LCD and exercise, and 15 followed neither program.  Group sessions of 8 - 15 subjects continued weekly for 6 months then monthly for 12 months.

Control Variables


Description of Actual Data Sample:

Initial N: 45 subjects, 15 on VLCD, 15 on LCD and 15 on neither program

Attrition (final N):  13 on VLCD completed, 12 on LCD completed

Age:  not mentioned

Ethnicity:  not mentioned

Other relevant demographics:

Anthropometrics:  not described in this article

Location:  United Kingdom


Summary of Results:



VLCD Baseline

VLCD 5 Years

LCD Baseline

LCD 5 Years

BMI 37.7 +/- 9.9 36.1 +/- 10.7

35.9 +/- 5.4

32.7 +/- 3.8

Waist (cm)

117 +/- 24

114 +/- 20

113 +/- 13

108 +/- 4

SBP (mm Hg) 139 +/- 17 143 +/- 13 142 +/- 22 130 +/- 20
DBP (mm Hg) 76 +/- 10 77 +/- 11 85 +/- 13 74 +/- 13
Glucose (mmol/l) 12 +/- 5 13 +/- 5 13 +/- 5 14 +/- 4
Fructosamine (umol/l) 352 +/- 84 348 +/- 59 385 +/- 98 357 +/- 88
Cholesterol (mmol/l) 6.8 +/- 1.2 5.7 +/- 1.3 5.9 +/- 1.3 5.3 +/- 1.5
Triglyceride (mmol/l) 3.9 +/- 3.4 2.9 +/- 2.3 2.4 +/- 1.3 2.5 +/- 1.5
HDL Cholesterol (mmol/l) 1.20 +/- 0.39 1.26 +/- 0.47 1.10 +/- 0.32 1.78 +/- 0.26

LDL Cholesterol (mmol/l)

3.85 +/- 1.57

3.42 +/- 1.38

3.83 +/- 0.73

3.25 +/- 0.65

Other Findings

Weight loss was slower in the intensive conventional diet group than in the VLCD group, but better maintained at 5 years:  group 1, 4.8 +/- 6 kg, group 2, 8.9 +/- 4 kg.

In the intensive conventional diet group, 5 year HDL cholesterol was increased by 1.78 +/- 0.26 mmol/l vs 1.10 +/- 0.32 mmol/l at baseline, and DBP reduced 74.5 +/- 13.3 vs 85.5 +/- 13.3 at baseline, both P < 0.05. 

Author Conclusion:

In this selected group of patients with type 2 diabetes (group 1 and 2), those successful with VLCD were able to safely achieve substantial weight loss for more than a year, which could allow major surgery to be carried out more safely.  Those prepared to follow group sessions of diet and exercise for a longer term were able to sustain substantial weight loss at 5 years (>8 kg) but not a remission in their diabetes.  This result may help in advising obese type 2 diabetic subjects on long and short-term success of these 2 strategies for weight loss.

Funding Source:
University/Hospital: Torbay Hospital Special Medical Grant Fund
Foundation associated with industry:
Reviewer Comments:

Methods for collecting data not described.  Subjects not well described.  Small numbers of subjects in groups.

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? ???
  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? ???
  2.2. Were criteria applied equally to all study groups? ???
  2.3. Were health, demographics, and other characteristics of subjects described? ???
  2.4. Were the subjects/patients a representative sample of the relevant population? ???
3. Were study groups comparable? ???
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) ???
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? ???
  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? ???
  4.1. Were follow-up methods described and the same for all groups? ???
  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%.) ???
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? ???
  4.4. Were reasons for withdrawals similar across groups? ???
  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? 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)? 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? No
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