A sustainable diet is defined as one that promotes food sustainability and ecological well-being.
Sustainable diets are eating patterns that look at the impact that food consumption has on planetary resources and health of humans and promote the needs of the environment, society, and the economy. This growing body of research is recognised by a variety of international bodies such as the United Nations Food and Agriculture Organization (FAO) and the World Health Organization (WHO).
A growing population and an increase in income is shifting global demands to what is known as the global diet. It demands a diet high in animal protein, oils, salts and processed foods.
Additional research and methods that will help address issues such as agriculture production methods, food waste, environmental problems like declination of biodiversity and global warming, are necessary for promoting sustainable diets. As well as to determine whether or not there should be concern on plant vs. animal diets and their impact on health.
In 2010, the FAO and Bioversity International defined a sustainable diet as:
those diets with low environmental impacts which contribute to food and nutrition security and to healthy life for present and future generations. Sustainable diets are 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.
Some so-called "sustainable" diets mostly concentrate on issues to do with Low Carbon Diets which are structured to reduce the impact of global warming (e.g., Bon Appétit Management Company's, Eat Low Carbon Diet).
Others also focus on broader environmental factors, as well as social and economic challenges (e.g., WWF's LiveWell for LIFE, and the Barilla Group's "Centre for Food Nutrition" model).
Other regionalized diets include the Mediterranean diet which was used as a basis in research published in 2014 to outline an approach to develop metrics and guidelines to measure the sustainability of diets in a way that useful to inform stakeholders, measure change and aid decision-making processes at regional and national scales.
The Nordic diet is also considered sustainable as it places a heavy emphasis on local foods. Professor Henrik Saxe of the OPUS Centre at the University of Copenhagen claims that GHG produced could be 27-percent lower in these emission in comparison with the average Danish diet.
There is research that states the importance of the role of animal agriculture to ensure Food security. It is the ability for people to have access to nutrient dense and safe food and can be achieved through animal agriculture given that it is a high quality and micronutrient rich source of food that supports a balanced diet.
The farming of animals comes with the benefit of improving soil conditions and the biodiversity of arable land. There is additional research in the field that reports that both high and low numbers of carbon emission is attributed to animal agriculture. Livestock is one of the major contributors to Greenhouse gas emissions. A solution to this issue is setting policies that target livestock practices from the supply side in order to address GHG while taking into consideration social and economic costs. It has been suggested that a more efficient livestock production system can lead to a decrease of emissions of 736 million metrics tons of carbon dioxide equivalent per year by 2030.
Zoonotic diseases, ones that are found in animals and transmitted to people, are a concern, specifically, for those that question animal agriculture. It was found that intensification of livestock production is related to an increase in disease transmission from animals like pigs and poultry due to a high density of these animal populations with low genetic diversity.
A lower consumption of animal-sourced foods is argued to bring positive benefits to the health of people and the environment. Dietary shifts studied are based on reductions of animal foods and an increase of plant-based foods and they show an increase in health in people adopting them.
As income increases the intake of calories from processed foods and the demand for animal protein increases. Demand for legumes, fruits and vegetables and plant protein decreases as income increases.
Diets that use the most land are the highest contributors to GHG emissions per capita and globally per year. One such diet from the Tilman and Clark study is the Income-dependent 2050 diet since it is a higher consumption of ruminant animals.
A vegetarian diet, relative to the income-dependent diets, is the highest contributor to cropland reduction compared to a pescetarian or mediterranean diet. It is also the smallest contributor to GHG emissions when compared to any other diet.
An important contribution to this debate is the European Commission's Roadmap to a Resource Efficient Europe. Amongst other things, this broad policy review looks at "incentives for healthier and more sustainable production and consumption of food and to halve the disposal of edible food waste in the EU by 2020."
As part of this new policy, a public consultation on the "Sustainability of the Food System" was launched in the summer of 2013, asking stakeholders for their opinion on how the food system must be adapted. This will go on to form a Communication on Sustainable Food by the European Commission. The European Parliament's 766 MEPs and the Member States of the Council will debate this Communication and makes, changes and vote on approval.
The indicative timeline for the consultation is as follows:July–1 October 2013: Consultation Sustainability of the Food System
December 2013: Impact Assessment
January 2014: EC Communication on Sustainable Food published
March 2014: Environment Council will discuss the proposal?
Spring 2014: European Parliament reaction
June 2014: Environment Council decides on legislative proposals?
2015: New legislation and policy recommendations enter into effect