Throughout the Mediterranean region, adherence to the Mediterranean diet is decreasing especially among young people. The Mediterranean diet is the most studied dietary pattern with proven health benefits, especially regarding the prevention of non-communicable diseases at a time when their incidence is increasing worldwide. It has also been recognized as a sustainable diet model with multiple interdependent benefits on social, cultural, environmental and economic dimensions.
Faced with the challenge of promoting adherence to the Mediterranean diet, a Joint Med Diet Task Force of CIHEAM, FENS, and IUNS was formed to set the path for reversing the erosion of the Mediterranean diet heritage, by promoting its benefits, as a way of living, as defined by UNESCO. In this paper, the rationale and propositions of the Joint Task Force are described for the development of a voluntary code of conduct for promoting the adherence of the Mediterranean diet, and sustainable diets per se, addressed to all interested stakeholders and rights holders, linking food consumption and production, toward sustainable food systems transformation in the Mediterranean and beyond.
Introduction: The problem of low adherence to the Mediterranean Diet
The Mediterranean diet is a widely accepted healthy diet supported by scientific evidence from epidemiology and clinical trials, including randomized control trials, and systematic reviews and meta-analyses (1-4). It is defined by the UNESCO in the inscription to the list of the Intangible Cultural Heritage of Humanity, as “a set of skills, knowledge, practices and traditions ranging from the landscape to the table, including the crops, harvesting, fishing, conservation, processing, preparation and, particularly, consumption of food. The MedDiet is characterized by a nutritional model that has remained constant over time and space, consisting mainly of olive oil, cereals, fresh or dried fruit and vegetables, a moderate amount of fish, dairy and meat, and many condiments and spices, all accompanied by wine or beverage infusions, always respecting beliefs of each community. However, the MedDiet (from the Greek ‘diaita’, or way of life) encompasses more than just food. It promotes social interactions, since communal meals are the cornerstone of social customs and festive events”(5).
The Mediterranean diet, recognized as a healthy dietary pattern (6-8), is also acknowledged as a sustainable diet model, linking nutrition and sustainable food systems (9-13).
Despite all its well documented benefits, the Mediterranean diet is almost abandoned in most Mediterranean countries. Scientific evidence shows a tendency of Mediterranean populations to change their dietary patterns in favor of unhealthy dietary patterns (14-17), and mainly among the young generation (18-28). Some Southern and Eastern Mediterranean countries are still experiencing the “nutritional transition”, first characterized in the early 1990s (29), in which problems of under-nutrition coexist with overweight, obesity and diet-related chronic diseases (30).
The traditional ways of consuming and producing food in the Mediterranean area have changed considerably, due to economic, social, cultural, demographic and technological trends, increasing globalization, urbanization, and shifting lifestyles with increased sedentary daily life (11). The erosion of the Mediterranean diet is alarming, as it has undesirable impacts not only on health and nutrition, but also on social, cultural, economic and environmental sustainability dimensions in Mediterranean countries. (12-13).
Current unhealthy and unsustainable food production and consumption patterns (fast and ultra-processed foods) have a strong negative impact on overall food systems sustainability (31-33).
The globalization of eating habits has overtaken traditional diets and increased sedentary lifestyles, also throughout the Mediterranean region and beyond.
Studies on the Mediterranean diet were/are mainly focused on health/nutrition impacts (physiological needs for energy, and macro- and micronutrients) of its characteristic foods, and recently also on its environmental impacts, while the importance of its cultural, social and economic food dimensions have been rather neglected, despite being shared by all Mediterranean peoples (34). In the last decade the notion of the Mediterranean diet has undergone a progressive evolution, from a traditional healthy dietary pattern to a sustainable diet model, a Mediterranean lifestyle (35-36-).
In people's daily lives, however, things do not work this way as daily food choices are influenced by economic, political, social, cultural and physical components, most of which are outside the control of the individual (37-38).
Voluntary code of Conduct – Case for Action
The rationale for co-developing the conceptual framework of the proposed Mediterranean diet voluntary code of conduct is based on the recognition that the challenges threatening the Mediterranean diet heritage are complex, interrelated, and context specific. Addressing them requires a sustainable food systems approach grounded in broad, multi-stakeholder collaboration and consensus, rather than fragmented, sector-specific solutions. (59).
Mediterranean food systems and diets have become increasingly detached from local food production (60). Given the intrinsic linkages among food production, consumption, and nutritional health, consumers occupy a pivotal role within food systems. Improving adherence to the Mediterranean diet requires the active involvement of consumers and all sectors, with regional cuisines, chefs and collective catering services playing an important educational role in fostering awareness and appreciation of local food biodiversity and the diversity of traditional foods and recipes (61).
The incorporation of sustainability issues into food based dietary guidelines has been steadily increasing over the past decades to make diets healthier for consumers as well as for the environment. However, this effort has not met universal approval. After the publication of the first dietary guidelines for sustainability (62), criticisms have continued to ignite controversial debates, particularly in the agriculture sector (63-65). Within this international debate on the transformation of sustainable food systems towards more sustainable dietary patterns, the value of the Mediterranean diet, a mainly plant-based dietary pattern, is acknowledged as a sustainable diet model (66-69).
The Mediterranean diet model offers significant opportunities to preserve health, culture and biodiversity while improving environmental, socio-cultural, and economic sustainable benefits. However, in spite of all this evidence, its adherence is decreasing. Many barriers may explain this, such as taste, cost, convenience, culinary preparation skills (70), time constraints, education, income, food environments, and the ubiquity of ultra-processed foods (71), which have been shown to be harmful for health (72). In 2004, the International Task Force on the Mediterranean Diet proposed “the possibility of defining the Mediterranean diet with certain openness that would acknowledge healthy changes, within this model that may have been produced over last 40 years, or that may come about in the future” (73). Such changes were expected to be beneficial for improving its adherence, without distorting its identity. For example, the PREDIMED study provides evidence that a slight modification of the traditional healthy Mediterranean diet can still benefit people at high cardiovascular disease risk (74).
Concerning affordability, a recent review concluded that the Mediterranean diet could be less costly than western diets and could bring a beneficial cost-benefit for health systems (75). Production intensification has also degraded agricultural landscapes, decimated ecosystem services, and contaminated foods and agri-food systems through excessive use of persistent and harmful agricultural chemicals, resulting in lower concentrations of nutritionally desirable compounds and/or higher concentrations of toxic compounds in many of the foods associated with the health benefits of the Mediterranean diet (76-77). For most populations, including in Mediterranean countries, livestock systems are by far the main factors associated with deleterious environmental impact, and, for many people, reducing their meat consumption is not easy (78). In the Spanish landscape called « Dehesa » the Iberian pork, sheep, goat, contributes to sustainability and the environment, and probably in other Mediterranean countries it is similar.
The Mediterranean diet emphasizes the use of local and seasonal products, thus reducing the environmental impact of food transportation and storage. In addition, the cultivation of olive trees, vineyards and other typical Mediterranean crops supports the local economy and preserves agri-cultural landscapes (79). In the past four decades, several pyramids represented the Mediterranean diet dietary pattern characteristics, However, these studies vary considerably in definitions and in defining the amounts of foods in grams and/or nutrients constituting the model (80). In 2020, through a consensus process, an updated version of the 2012 Mediterranean diet pyramid (81-82), more focused on its environmental impact was published. In 2025, an adapted version of a Mediterranean Lifestyle Pyramid addressed to children and adolescents was developed, through a consensus process by another group of experts (83).
The code
The voluntary code of conduct, through broad consultation, is addressed to promote the Mediterranean diet model by underscoring its common principles (84):
Aims of the code
The code will address the sustainability of the Mediterranean diet with the sustainable food systems approach of the SFS-MED Platform (59), considering sustainable food systems as a whole, rather than their separate parts, and going beyond disciplinary approaches and silos, as a web of interconnected and interdependent components within a decision-making very fragmented food environment, with a wide range of voices from different interest groups and agendas (59)
By taking into account this interdependent food environment , following cross-cutting domains, were initially identified:
These cross-cutting domains will be approached through a whole adaptive sustainable food systems perspective (85-86) to further understand their interconnectivity and how multifaceted factors across systemic levels can play a major role in the revitalization of the Mediterranean diet as a sustainable diet model, contributing to improve in the region food security and environmental, economic and social sustainability (66).
The code will begin with a preamble setting out the general justification. The preamble of the International Code of Marketing of Breast-milk Substitutes (87) has been used as a model for a sustainable diets’ code of conduct preamble, which in turn is applicable to the Mediterranean diet.
For the purpose of this exercise, the 2010 FAO definition of sustainable diets (11) has been modified and used as the ad hoc definition of the Mediterranean diet, as follows: “
…is a diet with low environmental impacts that contributes to food and nutrition security and to healthy life for present and future generations in the Mediterranean region. It is protective and respectful of biodiversity and ecosystems, culturally acceptable, accessible, economically fair and affordable; nutritionally adequate, safe and healthy; while optimizing natural and human resources. (11)” This definition is not to be construed as an official, proposed, or suggested definition for the Mediterranean diet, simply is being used as a surrogate or proposal for the specific purpose of this drafting exercise of the voluntary code of conduct.
Implementation process of the development of the voluntary code – how and by whom
In 2010, a consensus definition for sustainable diets was reached at the International Scientific Symposium “Sustainable diets and biodiversity: United against hunger”, by FAO and Bioversity International at the FAO headquarters, in Rome, in which an entire session was devoted to the Mediterranean diet as an example of a sustainable diet, and closed with a proposal for drafting a code of conduct for sustainable diets (11). In 2011, at the FAO/CIHEAM International Workshop “Guidelines for the Sustainability of the Mediterranean Diet”, at the CIHEAM-Bari, was started as a joint case study to assess the sustainability of the Mediterranean diet in the Mediterranean region, considering its multi-dimensions and impacts on health and nutrition, environment including biodiversity, economy, and socio–cultural factors (88-89). In 2016, at the first World Mediterranean Diet Conference “The Revitalizing the Mediterranean Diet: from a healthy dietary pattern to a healthy Mediterranean sustainable lifestyle” (90), “The Call for Action on the Revitalization of the Mediterranean Diet” was issued and endorsed by 35 international and national scientific institutions (91).
In 2017, this long-standing consensus process continued at the FAO/CIHEAM international workshop “Development of voluntary guidelines for the sustainability of the Mediterranean diet in the Mediterranean region”, held at the CIHEAM Bari (84). In 2019, at the Second World Mediterranean Diet Conference “Strategies toward more sustainable food systems in the Mediterranean region: the Mediterranean Diet as a lever for bridging consumption and production in a sustainable and healthy way” held in Palermo by CIHEAM-Bari and the Forum on Mediterranean Food Cultures (92), the issue of a voluntary code of conduct for the sustainability and adherence of the Mediterranean diet was raised again.
In 2022, at the Third World Mediterranean Diet Conference “A change of route: towards more sustainable and resilient food systems in the Mediterranean countries - The Mediterranean diet as a strategic resource for accelerating the Agenda 2030 in the Region” (93), by CIHEAM-Bari, as an outcome of the session “Assessing and promoting adherence to the Mediterranean diet”, a Joint Med Diet Task Force was initiated by FENS, IUNS Sustainable Diets Task Force, and CIHEAM-Bari to set the path for reversing the erosion of the Mediterranean diet, as a way of living in the Mediterranean.
The role of the Task Force was setting the path for creating, evaluating and implementing a common framework for a new Mediterranean Dietary Pattern for the 21st Century, by
(i) (re-)defining the Mediterranean Diet appropriate for the 21st Century;
(ii) reaching consensus, on the elements required to measure adherence to MedDiet, and, if possible, developing a single index;
(iii) drafting a voluntary code of conduct with recommendations for different sectors (primary producers, food industry, health, environment, food service and consumers, etc.) to improve adherence to sustainable Mediterranean Diets, using a rights-based approach, grounded in tradition, respectful of biodiversity and ecosystems, and consistent with Sustainable Development Goals.
In November 2023, at the 14th European Nutrition Conference FENS 2023, in Belgrade, the proposal of the voluntary code of conduct was further discussed within the double symposium “Measuring and Promoting Adherence to the Mediterranean Diet, as a Model for Sustainable Diet”, organized by the Joint Med Diet Task Force, and supported by CIHEAM-Bari.
In April 2024, a first Med Diet Joint Task Force’s meeting in person was organized by CIHEAM Bari, in Rome, with the scope to work more efficiently on the Task Force’s objectives, updating its ToRs and defining its road map 2024-2025 towards the development and implementation of a zero draft of a voluntary code for sustainable diets, adapted to the Mediterranean diet.
In August 2025, at the IUNS/ICN 2025 conference, in Paris, an overview update on the proposal development of the voluntary code of conduct was debated, within a dedicated symposium on “ A voluntary code of conduct for measuring and promoting adherence and sustainability of the Mediterranean diet:- rationale, proposition and challenges“, organized by the Joint Med Diet Task Force, The symposium was focused to set a path for reaching consensus on a voluntary code of conduct and a unified score, as safeguarding measures, to reverse the erosion of the Mediterranean diet by promoting and measuring its adherence and sustainability. The symposium ended by discussing next steps on how to lead the development and implementation process of the code as a broader collaborative effort, involving expertise from other fields not represented yet in the Task Force.