Changes in terms of risks/benefits of shifting diets towards healthier and more sustainable dietary models

Abstract

Food production and therefore human diet are identified as important sources of environmental impact. Unhealthy and unsustainable diets with high intake of meat and low intake of plant‐based products are predominant worldwide. On the other hand, a balance between health and sustainability is necessary, since diets that are environmentally sustainable could lack essential macro‐ and micronutrients and result in nutrient deficiencies, non‐communicable diseases and malnutrition. The aim of this project was to investigate the nutritional adequacy and environmental impact of adults' diet by comparing current dietary habits and new alternative dietary scenarios. First, a systematic review was conducted following PRISMA guidelines to assess the environmental impact of current diets and sustainable dietary scenarios such as vegan, vegetarian, pescatarian, omnivorous and optimised dietary patterns worldwide. In the second part of the project, an optimisation study was conducted, based on a multi‐objective optimisation approach, with the purpose of creating the optimal diet based on nutritional and environmental constraints for the adult Italian population. The dietary scenarios of the optimised models were developed in accordance with the Italian food‐based dietary guidelines. Food consumption data was extracted from the INHES study and used as baseline diet. A clear evaluation of the current environmental impact because of diet and potential sustainable dietary scenarios globally is challenging. Finally, national food‐based guidelines should be adjusted by suggesting healthy and sustainable dietary recommendations in line with traditional eating habits and local food availability in order the desirable dietary shifts towards sustainability to be feasible.

1. Introduction

Due to the technological innovations in agricultural sector, food availability and security have increased significantly. As a result, hunger, undernutrition, poverty and mortality have been reduced through the last years worldwide (Myers et al., 2017; Willett et al., 2019). However, diets with low vegetable, fruit, wholegrain and high in red and processed meat intake are dominant worldwide (Springmann et al., 2018; Kalmpourtzidou et al., 2020). As a result, high‐calorie diets and animal‐based protein sources have a negative impact both on health and environment (Heller et al., 2013; Willett et al., 2019; Grosso et al., 2020). Food production is responsible for the one‐third of global greenhouse gas emissions (GHGEs) on the planet (Whitmee et al., 2015; Myers et al., 2017; Crippa et al., 2021). The nutritional and economic transition in low‐ and middle‐income countries contributed largely to the double burden of malnutrition and high environmental impact of diets in these countries (Gill et al., 2015; Miller et al., 2016; Batal et al., 2018; Kalmpourtzidou et al., 2020). Therefore, a dietary shift to alternative, more sustainable choices is necessary.

According to Food Agriculture Organization (FAO), sustainable diets are defined as ‘those diets with low environmental impacts which contribute to food and nutrition security and to healthy life for present and future generations’ (FAO, 2010). EAT‐Lancet Commission defined global targets for sustainable diets and food systems taking into consideration environmental, nutritional and health factors (Willett et al., 2019). Even though the planetary health diet proposed by EAT‐Lancet Commission could have a positive effect both on health and the environment, the eating habits, traditions and food availability of each country are taken into account, separately (Willett et al., 2019). Numerous studies in the last years have been conducted with the aim to evaluate the effect of the current diets and alternative diets on the environment and health. Vegetarian, Mediterranean and the New Nordic diet are some of the dietary patterns that could be considered sustainable (Aleksandrowicz et al., 2016).

Consequently, the main goal of the specific project, as part of the European Food Risk Assessment (EU‐FORA) fellowship programme was initially to systematically review the environmental impact of the current diets and alternative diets worldwide. Based on these results, the current Italian diet was optimised by minimising its GHGEs and meeting the national food‐based dietary guidelines (FBDGs) and the National Recommended Energy and Nutrient Intake Levels (LARN) proposed by the Italian Society of Human Nutrition (SINU).

2. Description of work programme

2.1. Aims

The aim of this project was to investigate the nutritional adequacy and environmental impact of adults' diet by comparing current dietary habits and new alternative dietary scenarios. To this purpose, firstly a systematic review and afterwards an optimisation study were conducted. The systematic review aimed to understand and analyse the sustainability of current diets worldwide in comparison to alternative diets in relation to their environmental impact. The objective of the optimisation study was to build optimal sustainable dietary models for the adult Italian population using the current Italian diet as baseline diet and taking into consideration the Italian FBDGs and LARN.

2.2. Activities/methods

2.2.1. Systematic review

In the first part of the project, a systematic review was conducted following PRISMA guidelines to assess the environmental impact of current population diets and alternative sustainable dietary scenarios such as vegan, vegetarian, pescatarian, flexitarian, including optimised dietary patterns worldwide. Scopus, Web of Sciences and Pubmed were searched for available data from October 2021 to January 2022. The key strings were adjusted based on the database searched. Only original studies, conducted and published from 2000 onwards, in English language, quantitatively assessing the nutritional and environmental impact of dietary patterns in healthy adult populations, were included.

2.2.2. Optimisation study

The analysis of health and environmental impact of more sustainable diets have been widely investigated in the last years in Europe (Laine et al., 2021). However, the attempts to optimise the Italian diet have been performed based on the last National Food consumption Survey INRAN‐SCAI 2005–2006 (Leclercq et al., 2009), which does not represent the current dietary habits in Italy. Therefore, to allow a better reliability of the optimisation study, the use of food consumption data from the INHES study has been considered a preferable solution to better represent the most recent food consumption in Italian population (Pounis et al., 2017). In INHES, adults older than 18 years were recruited and 24‐h recalls were collected for the food consumption assessment. The EFSA Food classification and description system for exposure assessment (FoodEx2) (EFSA, 2017) was applied for the extraction of food consumption data (Pounis et al., 2017).

The optimisation modelling was based on the multi‐objective optimisation approach proposed by Donati et al. (2016). Specifically, a linear programming model was developed, and constraints related to the nutrients requirements per age and sex based on LARN (SINU, 2014), the frequency of food groups consumption based on the Italian FBDGs, alternative plant‐based protein food products, acceptability and environmental impact indicators were applied. The nutritional constraints have been drawn up taking into account daily energy requirements distinguishing between men and women, and the different sources of energy. The model incorporated restrictions on energy and macronutrients according to LARN recommendations. The optimal combination of food products was obtained minimising the environmental impact and specifically the GHGEs of the diet. The objective functions were represented algebraically as follows:

1. Nutrients intake:

$$\sum _{\mathrm{i}}\sum _{\mathrm{j}}{\text{food}}_{\mathrm{i},\mathrm{j}}{\mathrm{a}}_{\mathrm{i},\mathrm{k}}\ge {\mathrm{low}}_{\mathrm{k}}\forall \mathrm{k},$$

$$\sum _{\mathrm{i}}\sum _{\mathrm{j}}{\text{food}}_{\mathrm{i},\mathrm{j}}{\mathrm{a}}_{\mathrm{i},\mathrm{k}}\le {\mathrm{upp}}_{\mathrm{k}}\forall \mathrm{k},$$

where food_i,j: food item i of food category j; a_i,k: coefficients of energy and macronutrients k per gram of food i; low_k and upp_k: lower and upper level of nutrients, respectively.

2. FBDGs recommendations:

$$\sum _{\mathrm{i}}{\text{food}}_{\mathrm{i},\mathrm{j}}\le {\text{port}}_{\mathrm{j}}\left(1+0.10\right)\forall \mathrm{j},$$

where port_j: portion associated with each food category.

3. GHGEs minimisation:

$$\underset{{\text{food}}_{\mathrm{i},\mathrm{j}}\ge 0}{\min }\mathrm{MEM}=\sum _{\mathrm{i}}\sum _{\mathrm{j}}{\text{food}}_{\mathrm{i},\mathrm{j}}{\mathrm{em}}_{\mathrm{i}},$$

where MEM: minimise carbon dioxide with food item specific impact em_i (CO₂ emissions).

3. Conclusions

3.1. General conclusions of the project results

The results of the studies included in the systematic review vary within and in‐between countries regarding the environmental impact of current and alternative diets. Ideally, common methodology regarding current food consumption and environmental impact assessment should be used to have comparable and harmonised results. Optimised dietary models have a lower CO₂ footprint, especially diets identified as sustainable or sustainable and healthy, than dietary scenarios based on literature. Comparing current diets to sustainable and health scenarios/models created per country, meat and dairy products consumption should decrease, while fruit, vegetable, fish and egg consumption should increase. National nutrition surveys instead of food supply/purchase or FAOSTAT food balance sheets should be used as baseline diets for the constructions of more sustainable and healthy scenarios to avoid the overestimation of current food consumption. Additionally, available data derived mainly from high‐income countries, thus low‐ and middle‐income countries are underrepresented. In order to have a holistic overview of the environmental impact of the diets, further research is needed and should target low‐ and middle‐income countries. Finally, the construction of optimal sustainable diets is complex. Multiple constraints need to be considered to propose diets being healthy, nutritious, acceptable, affordable, and environmentally sustainable for the general population.

3.2. Scientific activities of the fellowship

3.2.1. Optimisation course

The fellow followed the course ‘Economical modelling and environmental policies’, part of the MSc programme ‘Sciences and technologies for environment and resources’ of the University of Parma, taught by Professor Michele Donati. The knowledge of the construction of mathematical programming models and the use of related programming tools, such as the General Algebraic Modelling System (GAMS), helped the fellow to understand the optimisation modelling methodology for the construction of the sustainable optimal dietary models.

3.2.2. Poster presentation

The fellow made a poster presentation at the National Conference Italian Society of Human Nutrition 2022 that took place in Naples, Italy. Part of the results of the systematic review were presented. Current diets and alternative dietary scenarios and their environmental impacts in South Europe were the main focus.

3.2.3. Conferences and webinars (Table 1)

Table 1.

Conferences and webinars followed by the fellow

Title	Type of activity	Organiser/Tutor	Date
Towards the Future of Food: the Cultured Meat between Food Safety, Sustainability and Public Perception	Webinar	University of Parma	27/9/2021, 10.00–13.00 CET
Sustainable and Healthy Diets Webinar 1: Introducing the concept and context of sustainable healthy diets Webinar 2: Current policies and global initiatives on sustainable and healthy diets Webinar 3: Revision of current Food Based Dietary Guidelines and policy required Webinar 4: The food cycle: from farming and sourcing to packaging and food waste Webinar 5: Applying Sustainability in Dietetic Practice	Webinar series	EFAD	16/9/2021–31/5/2022
Climate Change, biodiversity and nutrition: promoting healthy diets from efficient, inclusive, resilient and sustainable food systems	WHO Side Event at Pre‐COP26	FAO	10 January 2021, 14:00–15.30 CEST
Alimentazione e tumori (Nutrition and tumors)	Conference	SINU	22/10/2021, 9.00–13.00 CET
Life Cycle Assessment for sustainability food systems: integrating nutritional and environmental assessment	Webinar	FAO	27/10/2021, 9.30–10.30 CEST
EAT‐GlobeScan Consumer Research on a Sustainable Food System	Webinar	EAT	29/10/2021,
Achieving Healthy Diets from Sustainable Blue Food Systems in Small Island Developing States	WHO Side Event at COP26	WHO	11 February 2021, 18:00–19:00 CET
Changing Behaviour: From Policy to table. Moving the Dial towards Healthy Sustainable diets	E‐symposium	Alpro Foundation	17/11/2021, 14:00–16:20 CET
Shifting our food systems to support sustainable eating for climate and public health	E‐symposium	Oatly	12 September 2021, 14:00–18:15 CET
Vivi l'esperienza sostenibile (Live the sustainable experience)	Conference	SINU	14/12/2021, 9.00–17.30 CET
XLII National Conference Italian Society of Human Nutrition (SINU) 2022	Conference	SINU	04–4 June 2022
How can chefs help to save the planet? Discover the Life Climate Smart Chefs project	Webinar	Barilla Foundation	24/5/2022, 16:00–17:30 CET
Fruit and Vegetables for Sustainable Healthy Diets (FRESH)	Webinar	IFPRI	25/5/2022, 15:30–17:00 CET
Why consider soy alternatives to dairy and meat: Building a healthy, sustainable diet	Webinar	Alpro Foundation, Fuji Foundation for Protein research	14/6/2022, 9.00–11.30 CET
One Health Conference 2022	Conference	EFSA	21–24/06/2022

3.3. Additional information

Manuscripts reporting detailed results of the systematic review and the optimisation study are in preparation and will be submitted to peer‐reviewed journals. Publications will follow after the end of the fellowship programme.

Abbreviations

EFAD

European Federation of the Associations of Dietitians

EU‐FORA

European Food Risk Assessment

FAO

Food Agriculture Organization

FBDGs

food‐based dietary guidelines

GHGEs

greenhouse gas emissions

IFPRI

International Food Policy Research Institute

INHES

the Italian Nutrition and Health Survey

LARN

Livelli di Assunzione di Riferimento di Nutrienti ed energia (National Recommended Energy and Nutrient Intake Levels)

SINU

Società Italiana di Nutrizione Umana (Italian Society of Human Nutrition)

WHO

World Health Organization

Suggested citation: Kalmpourtzidou A and Scazzina F, 2022. Changes in terms of risks/benefits of shifting diets towards healthier and more sustainable dietary models. EFSA Journal 2022;20(S2):e200904, 8 pp. 10.2903/j.efsa.2022.e200904