VN: Types and Diversity of Vegetarian Diets (2009)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
  • Leaders within the raw foods community were targeted for indepth interviews to provide insights into the scope of practices being advocated and modeled for the larger raw foods community. It is intended that health and nutrition educators who provide counseling will gain a basic understanding and awareness of attitudes, beliefs and dietary practices of raw foodists. 
  • The study aimed to:
    • Describe the range of raw food dietary practices espoused by individuals identified through the literature as leaders within the US raw foods movement
    • Examine the rationale for adoption of a raw foods diet
    • Identify related attitudes and health practices or characteristics associated with a raw foods lifestyle.
Inclusion Criteria:
  • A purposeful sample of leaders within the raw foods community was obtained by tabulating names of authors, lecturers and retreat leaders located in print materials and through internet raw foods communities
  • Subsequent snowball sampling identified additional subjects for a total of 17 informants.
Exclusion Criteria:

None stated.

Description of Study Protocol:

Recruitment

  • Leaders within the raw foods community were identified through a literature search and subsequent snowball identification of additional leaders
  • All study participants provided written and oral informed consent to the study. 

Design

  • The study was nonexperimental and was descriptive in design
  • Qualitative data from semistructured key informant interviews were collected through recorded telephone interviews
  • Interview questions were pilot-tested and revised as necessary before further interviews were conducted. 

Blinding

None.

Intervention

None.

Statistical Analysis

  • Text analysis and simple descriptive statistics
  • Qualitative data were managed and organized using CDC EZ-Test software version 3.06 which included a multi-step coding procedure and preparation of matrices and data summaries conducted solely by the principal investigator
  • Coded responses were reviewed again one year later by the principal investigator and no changes were made in organization or interpretation of interview data. 
Data Collection Summary:

Timing of Measurements

  • Telephone interviews were conducted between March 2002 and August 2002
  • Length of interviews were 30 to 90 minutes each with an average of one hour. 

Data

  • The author conducted all interviews
  • Telephone interviews were conducted in a conversational manner so the order of the questions and specific wording varied
  • Interview questions included definitions of raw foods diets, rationale for adopting a raw foods diet and personal dietary practices, attitudes, beliefs and experiences of participants about diet and related health issues
  • Interviews were audiotaped and verbatim transcripts were made of each interview
  • A 24-hour dietary recall was conducted for each participant followed by a food frequency summary.
Description of Actual Data Sample:
  • Initial N: 17 (11 males, 6 females) 
  • Attrition: None, except for questions of perceived benefits of consuming a raw food diet where N=15. No explanation on why two participants did not provide answers.
  • Mean age: 46 years (range 31 to 69 years)
  • Ethnicity: Not stated
  • Other relevant demographics:

Characteristics N=17 %
College graduate total

13

76

   Bachelors degree

4

 24

   Advanced degree

9

69

Others live in household

13

 76

Member of spiritual or philosophic group

4

24

  • Anthropometrics: Height, weight and frame size were self-reported by participants. The author estimated ideal body weight (IBW) and BMI.  

  Men Women
  Range % Mean % Range % Mean %
IBW 85-122 98 93-112 98
BMI (kg/m2) 20-25 21.5 17-26 20

  • Location: Not stated, except the subjects were US leaders. 

 

Summary of Results:

Subjects defined characteristics of raw foods diets:

  • Contain no cooked foods
  • Foods not heated beyond a certain temperature (e.g., 1200°F, 1180°F, 1150°F to 1200°F, 1080°F) 
  • Have their enzymes intact as a result of not being cooked
  • Raw foods have their life force present.

Subjects defined characteristics of living foods diets:

  • Being composed of foods that are alive at the time they are eaten
  • The time between harvest and eating is minimal
  • Include sprouted foods
  • Include cultured foods
  • Include foods that are still growing
  • Are those which enzymes are still intact. 

Perceived Benefits and Challenges of Consuming Raw Food Diet 

Perceived Benefits N (Total N=15)                  %                         
Health Advantages  9  60
    Protection from disease  3  20
    Faster healing  2  13
    Better digestion  1  7
    No longer hoarse  1  7
    Harder to sunburn  1  7
Weight  6  40
Subject has more energy  5  33
Greater connection with nature  3  20
Need less sleep  3  20
Increased mental clarity  3  20
More nutrients in diet  3  20
Food has more life force, energy or vital force  2  13
Feels lighter  2  13
Increased sense of happiness  2  13
Other  1  7

Perceived Challenges                                  N (Total N=17)                 %                         
Social pressures 11 65
Adjusting to the change in eating habits    4 24
Addictions to foods outside the eating plan 2 12
Finding organic foods 2 12
Other 1 6

  • Subjects reported having followed their raw foods diets for an average of 13 years, with a range of three to 32 years 
  • All 17 subjects consistently age a vegetarian diet and none included meat, fish or poultry in their diet 
  • One subject reported eating a small quantity of dairy products on rare occasions which made the subject a lacto-vegetarian
  • One subject admitted to eating honey. Excluding the subjects using dairy and honey, 88% ate a vegan diet.
  • 94% (N=15) reported being regularily physically active with participation in weight lifting (31%), yoga (31%) and running (31%) as being most reported. 

Food Frequency Over A Typical Week

Food N  (Total N=17)  %
Fruits and fruit juices 16 94
Vegetables 17 100
Grains 7 41
Legumes 3 18
Nuts and seeds 13 76
Dairy products 0 0
Eggs 0 0
Meat, fish, poultry 0 0
Oil or fat 17 100
Commercial sweets 0 0
Alcohol 0 0

Food Intake Patterns

Specific foods consumed were not listed, only how the food grouping fit into the regular Food Guide Pyramid and Vegetarian Food Guide Pyramid.  

Self-Reported Daily Intakes Compared to Two Recommended Eating Patterns

The Food Guide Pyramid

 Food  # Recommended Servings  # Servings Consumed (Average and Range)
Milk, yogurt and cheese  2-3  0
Meat, poultry, fish, dry beans, eggs, and nuts  2-3  2 (0-4)
Vegatables  3-5  9 (0-20)
Fruit  2-4  7 (1-19)
Bread, cereal,rice, and pasta  6-11  0 (0-3)
Fats, oils, and sweets  Use sparingly  3 (0-7)

 The Vegetarian Food Guide Pyramid

 Food # Recommended Servings # Servings Consumed (Average and Range)
Calcium-rich foods  8  2 (0-8)
Legumes, nuts, and other protein-rich foods  5  2 (0-4)
Vegetables  4  9 (0-20)
Fruits  2  7 (1-9)
Grains  6  0 (0-3)
Fats  2  3 (0-7)

Other Findings

All 17 subjects (100%) ate a vegetarian diet consisting of no meat, fish, eggs or poultry. Only one ate small quantities of dairy on rare occasions (making that subject a lacto-vegetarian) and one subject ate honey. Most interpretations of a vegan diet exclude honey. Excluding the subjects using dairy and honey, 88% of subjects ate a vegan diet. This study was about a subset of vegan diets: Raw foods diet.

Author Conclusion:
  • The author noted that a limitation of the study was that a small, nonrandom sample was used and therefore the results could not be generalized to the larger population of individuals who consume raw foods diet. The findings of this study should be useful for health counselors to know what leaders within the raw foods community are advocating and modeling to those aspiring a raw foods lifestyle. 
  • The author, after a review of the scientific literature, found relatively little information about raw foods or living foods diets. This study added considerably to the very small body of knowledge about attitudes and beliefs of those following a raw foods diet.
  • Qulified dietary guidance and support may be prudent for individuals follwing an eating pattern outside the cultural norm 
  • This study is consistent with findings from earlier studies that suggest it might be necessary to add a reliable source of vitamin B12 to the diets of long-term raw foodists
  • Further research is needed on larger populations of raw foodists to validate findings and also examine food-handling and preparation practices that may relate to issues of food safety associated with raw produce. 
Funding Source:
University/Hospital: University of North Carolina at Chapel Hill
Reviewer Comments:
  • I agree with the author's conclusion of the limitations of the study due to the small sample studied. The knowledge, beliefs and food choices of the subjects studied, US leaders in the raw food movement, may not be typical of the average person attempting to eat this way. 
  • I agree with the author's suggestion that qualified dietary guidance and support may be prudent for individuals following an eating pattern outside the cultural norm such as a raw foods diet
  • It was not explained why two participants did not provide answers to the perceived health benefits, exercise participation and some other questions about beliefs about a raw foods diet 
  • No mention was made as to the number of interview questions and the content of some of the test questions was only provided in a few instances
  • Self-reported and anecdotal answers to questions are more vulnerable to measurement errors and may even prove more difficult if the number of subjects was increased
  • The author is a professor at the University of North Carolina at Chapel Hill and was the primary author of the ADA position papers in 1988 and 1993 on vegetarian diets. 
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
  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
  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
  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
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
 
Validity Questions
  1. Was the research question clearly stated? Yes
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.1. 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
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
  1.3. Were the target population and setting specified? Yes
  2. Was the selection of study subjects/patients free from bias? 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
  2.1. 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? ???
  2.2. Were criteria applied equally to all study groups? ???
  2.3. Were health, demographics, and other characteristics of subjects described? 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
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
  3. Were study groups comparable? N/A
3. Were study groups comparable? N/A
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  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? 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? 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
  3.5. 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
  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? N/A
4. Was method of handling withdrawals described? N/A
  4.1. Were follow-up methods described and the same for all groups? ???
  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%.) N/A
  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%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? ???
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? ???
  4.4. Were reasons for withdrawals similar across groups? N/A
  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
  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. 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
  5.1. 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
  5.2. 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
  5.3. 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
  5.4. 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
  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. 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? N/A
  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? N/A
  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? N/A
  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
  6.4. 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
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments 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
  6.7. 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
  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. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? N/A
  7.1. Were primary and secondary endpoints described and relevant to the question? N/A
  7.2. Were nutrition measures appropriate to question and outcomes of concern? N/A
  7.2. Were nutrition measures appropriate to question and outcomes of concern? N/A
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? N/A
  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
  7.4. 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? N/A
  7.5. Was the measurement of effect at an appropriate level of precision? N/A
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.7. Were the measurements conducted consistently across groups? 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? N/A
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? N/A
  8.1. Were statistical analyses adequately described and the results reported appropriately? 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
  8.2. 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? No
  8.3. Were statistics reported with levels of significance and/or confidence intervals? No
  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
  8.4. 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
  8.5. 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? N/A
  8.6. Was clinical significance as well as statistical significance reported? N/A
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
  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? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? N/A
  9.1. Is there a discussion of findings? N/A
  9.1. Is there a discussion of findings? N/A
  9.2. Are biases and study limitations identified and discussed? N/A
  9.2. Are biases and study limitations identified and discussed? N/A
  10. Is bias due to study's funding or sponsorship unlikely? ???
10. Is bias due to study's funding or sponsorship unlikely? ???
  10.1. Were sources of funding and investigators' affiliations described? No
  10.1. Were sources of funding and investigators' affiliations described? No
  10.2. Was the study free from apparent conflict of interest? ???
  10.2. Was the study free from apparent conflict of interest? ???