AWM: Eating Frequency and Patterns (2013)


Uchigata Y, Iwamoto Y. Survey of dietary habits in obese patients with type 2 diabetes treated with either OHA or insulin injections in Japan. Diabetes Res Clin Pract. 2007; 77(3): 371-376.

PubMed ID: 16911841
Study Design:
Cross-Sectional Study
D - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To elucidate the dietary habits of obese patients with type 2 diabetes on antidiabetic medication using a one-week dietary questionnaire without involving the attending physicians.

Inclusion Criteria:
  • Type 2 diabetic patients on oral hypoglycemic agents or insulin in addition to medical nutrition and physical activity therapies
  • BMI higher than 25 
  • Medical nutrition therapy was introduced at the start of diabetes treatment.
Exclusion Criteria:

None noted.

Description of Study Protocol:


Recruited using three methods:

  • Mail method: Some subjects were extracted by mail monitoring via a survey company and informed consent was obtained
  • Web method: Some subjects were extracted via Web monitoring by a survey company and informed consent was obtained
  • Opportunistic method: Some subjects attending one of a number of affiliated hospitals were introduced by their attending physician. 


Cross-sectional study.

Blinding Used

Excluded physicians who instruct patients to complete medical nutrition therapy from the survey, a central registration center was established, and responses were directly collected from all patients.


 A one-week (seven-7 days) questionnaire survey regarding:

  • Meals and snacks (calorie content and time of eating)
  • Recent HbA1c levels
  • Recent medications.

Statistical Analysis

The two groups (oral hypoglycemic agents group and insulin group) were evaluated for mean deviations and proportional deviations, with a level of significance set at 0.05.

Data Collection Summary:

Timing of Measurements

Data collected for seven days (one week).

Dependent Variables

  • Daily calorie intake
  • Timing of three meals
  • Distribution of the timing of snacks and snacking frequency
  • BMI
  • Treatment (OHA or insulin)
  • Gender
  • HbA1c.

Independent Variables

  • Oral hypoglycemic agent group
  • Insulin group.
Description of Actual Data Sample:
  • Initial N: 240 total patients (139 males, 101 females)
  • Attrition (final N): 240 total patients (139 males, 101 females) 
    • Oral hypoglycemic agent group: 64.7% males and 35.3% females
    • Insulin group: 42.1% males and 57.9% females
  • Age: Average age was 52.9±13.4 years
  • Other relevant demographics:
    • Average duration of diabetes was 9.3±8.2 years (only significant difference between the two groups was duration of diabetes)
    • Average HbA1c was 7.3±1.2%
    • Of the oral hypoglycemic agents group (N=133):
      • 27.1% were taking glibenclamide
      • 27.1% were taking glimepiride
      • 11.3% were taking gliclazid
      • 9.8% were taking metformin
      • 9.0% were taking alpha-glucosidase
      • 6.0% were taking nateglinide
      • The remaining percent did not know what medication they were taking
  • Anthropometrics: Average BMI was 27.8±2.9. There was no significant difference in the clinical background of the subjects in the two groups except for duration of diabetes.
  • Location: Japan.
Summary of Results:

Key Findings

  • Association of daily calorie intake with treatment, BMI, gender and HbA1c:
    • In regards to a relationship between BMI and calorie intake, there is a weak positive correlation coefficient of 0.277 for the male oral hypoglycemic agent group only
    • In the relationship between HbA1c and caloric intake, a weak positive correlation was noted only for the female insulin group
  • Timing of the three meals and calorie content:
    • Timing of breakfast peaked between 7:00 and 9:00 a.m. for both groups
    • About 60% of subjects consumed breakfast between 7:00 and 8:00 a.m.
    • 8.6% of subjects reported they did not consume breakfast
    • Average daily calorie intake at breakfast was between 400 and 600kcal
    • Approximately 50% of patients had lunch between 12:00 noon and 1:00 p.m. with approximately 30% of the patients having lunch between 1:00 and 2:00 p.m.
    • 4.2% of subjects reported not consuming lunch
    • Most patients consumed dinner at 7:00 p.m. with 1.3% of patients reporting they did not consume dinner
    • The peak calorie intake at dinner was 600 to 800kcal in the oral hypoglycemic agent group and 400 to 600kcal in the insulin group
    • No significant difference between the two groups for breakfast, lunch or dinner
    • Calorie intake was highest at dinner, followed by lunch and breakfast
  • Distribution of the timing of having snacks for one week and snacking frequency
    • 88.5% of males and 98.2% of females reported habitual snacking
    • In the females, the frequency of having snacks between 6:00 a.m. and 8:00 p.m. was higher than in the males
    • The proportions of females having snacks at 10:00 a.m., 3:00 p.m. and 5:00 p.m. were significantly higher
    • 94.4% of insulin group patients and 91.7% of oral hypoglycemic-agents patients reported eating snacks and a significant difference was found at 3:00 p.m. with the insulin group snacking more than the oral hypoglycemic agent group
    • No significant correlations were found between the number of daily doses of medication for the oral hypoglycemic agent group and the timing of snacks
    • In the relationship between the number of insulin injections and the timing of snacks for the insulin group, snacking occurrence was comparatively high at 10:00 a.m. and 3:00 p.m.
    • A higher proportion of patients receiving a single shot per day had snacks at 10:00 a.m. and 3:00 p.m. in comparison to patients receiving two or more shots per day
    • There was no injection frequency-related difference in snack calorie intake
    • The relation between snack caloric intake and the treatment method, BMI, gender and HbA1c was investigated, but no significant correlation was noted for any factor. 
Author Conclusion:
  • Daily calorie intake was not correlated with gender, BMI, medication or HbA1c
  • Calorie intake was the highest at dinner, followed by lunch and then breakfast
  • Only for dinner was the caloric intake significantly higher for the oral hypoglycemic agent group than for the insulin group
  • To compensate for the 8.6% of patients that skipped breakfast, patients in both groups reported snacking around 8:00 a.m. and 9:00 a.m. and snacking was relatively common for the insulin group, particularly from 9:00 a.m. to 10:00 a.m. at about 10%. This may reflect the current dietary habit.
  • At least 90% or more of the patients reported habitual ingestion of snacks; nearly 100% of the females reported snacking with a snack consisting of up to 300kcal per time and is common at the times of 10:00 a.m., 3:00 p.m. and 5:00 p.m.
  • There was no marked difference in the proportion of patients having snacks between the two groups, with the insulin group snacking at a higher frequency than the oral hypoglycemic agent group at 3:00 p.m. only
  • Subjects injecting insulin once daily snacked at a high frequency at 10:00 a.m. and 3:00 p.m., with the next highest frequency at 8:00 p.m.
  • This survey failed to elucidate whether the obese diabetes subjects on anti-diabetic medication who participated in this survey had to commence pharmacotherapy because they were originally unable to control their blood sugar with medical nutrition and physical activity alone, or whether they became obese because of their medication
  • The survey indicated discrepancies between actual dietary habits and the medical nutrition therapy guidance given to patients
  • Non-stressful medical nutrition therapy should be performed in accordance with individual patients' lifestyles. When hypoglycemia occurs without snacks in such patients in this study, medication therapy must be reconsidered to prevent hypoglycemia.
Funding Source:
Other: unknown
Reviewer Comments:

Large sample.

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.) 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.) 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? N/A
  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? ???
  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? ???
  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? 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? 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? ???
  8.1. Were statistical analyses adequately described and the results reported appropriately? No
  8.2. Were correct statistical tests used and assumptions of test not violated? ???
  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)? ???
  8.6. Was clinical significance as well as statistical significance reported? ???
  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? ???
  10.1. Were sources of funding and investigators' affiliations described? No
  10.2. Was the study free from apparent conflict of interest? ???