Development of an index to assess adherence to the Traditional Chinese Dietary pattern - a modified Delphi study

Introduction
Adhering to traditional diets could significantly contribute to enhancing health and
promoting environmental sustainability (1). China reports the highest incidence of noncommunicable disease related fatalities globally (1). There has been no consistent
definition of the traditional Chinese diet (TCD). Findings on the association between
TCD and health outcomes are also inconsistent (2). Therefore, it is critical to establish
a consensus on the definition of the TCD, including food groups that are characteristic
of this diet and their quantities. The Delphi method is widely accepted as an effective
tool for consensus-building among experts (3). Hence, this study aimed to 1) establish
an index for assessing adherence to the overall TCD, involving inviting nutrition
experts to achieve a consensus on which food groups, food quantities, and food-related
habits define the TCD; and 2) develop five indices that characterise regional TCDs (for
the eastern, western, southern, northern, and central Chinese regions).
Methods
From October 2023 to February 2024, a three-round modified Delphi study was
conducted via an online platform. The eligible participants were nutrition experts,
working in various fields, including academic professors, registered dietitians, and
clinical nutrition physicians. Participants were invited to complete online
questionnaires, to establish the food groups and food-related habits that characterise
TCD by using a mix of Likert scales, a list of responses, and yes/no questions. Openended and free-text questions were also used to collect detailed comments/suggestions.
Consensus was assessed by using percentages of agreement; median values and
interquartile ranges were used to illustrate the recommended consumption ranges for
each food group to be included in the index. Statistical analyses were performed using
SPSS and NVivo 12.
Results
Fifty-eight nutrition experts (a minimum of ten experts from each region) were involved
in the first Delphi round. Response rates for the second and third rounds were 87.9%
and 93.1%, respectively. The resulting overall TCD index comprises 15 food groups
plus one dietary habit, with scores ranging from 0 to 23 (minimum to maximum), where
higher scores reflect higher adherence to TCD. Rice, various vegetables, fruits,
eggs/egg products, wheat/wheat products (excluding wheat with filling), and starchy
roots and tubers scored two points when meeting the consumption range. Wheat with
filling, pork/pork products, fermented foods, deep-fried wheat, corn/coarse grains,
legume products, beef/beef products, poultry and cooking by steaming and/or boiling
were scored one point each when meeting the consumption criteria. Five regional TCD
indices, including food groups and the range of quantities for each food group, were
also developed.
Conclusion
This modified Delphi study achieved consensus for developing TCD index and five
regional TCD indices for the first time. These indices can be utilised as essential
instruments for future research on exploring adherence to TCD and its impacts on health
outcomes and environmental sustainability