Toward healthy and sustainable diets for the 21st century: Importance of sociocultural and economic considerations.

Four years after the EAT-Lancet landmark report, worldwide movements call for action to reorient food systems to healthy diets that respect planetary boundaries. Since dietary habits are inherently local and personal, any shift toward healthy and sustainable diets going against this identity will have an uphill road. Therefore, research should address the tension between the local and global nature of the biophysical (health, environment) and social dimensions (culture, economy). Advancing the food system transformation to healthy, sustainable diets transcends the personal control of engaging consumers. The challenge for science is to scale-up, to become more interdisciplinary, and to engage with policymakers and food system actors. This will provide the evidential basis to shift from the current narrative of price, convenience, and taste to one of health, sustainability, and equity. The breaches of planetary boundaries and the environmental and health costs of the food system can no longer be considered externalities. However, conflicting interests and traditions frustrate effective changes in the human-made food system. Public and private stakeholders must embrace social inclusiveness and include the role and accountability of all food system actors from the microlevel to the macrolevel. To achieve this food transformation, a new "social contract," led by governments, is needed to redefine the economic and regulatory power balance between consumers and (inter)national food system actors.

The importance of protein variety in a higher quality and lower environmental impact dietary pattern.

OBJECTIVE: Eating a variety of nutritious foods is fundamental to good nutrition. However, this principle is challenged when recommendations seeking to improve the environmental sustainability of diets call for avoidance of foods considered to have a higher environmental footprint, such as animal-sourced foods. Our objective was to assess the implications for nutritional adequacy of protein choice across Australian adult diets preselected as having higher quality and lower environmental impact scores. DESIGN: Each individual diet was assessed for variety of food choice within the 'Fresh meat and alternatives' food group defined in the Australian Dietary Guidelines, which includes protein-rich foods such as eggs, nuts, tofu and legumes in addition to animal meats. Diets were grouped according to variety score and whether they included only animal meats, only alternatives or a variety of meat and alternatives. Nutrient content was assessed relative to estimated average requirements (EAR). SETTING: Australia. PARTICIPANTS: 1700 adults participating in the Australian Health Survey. RESULTS: For diets with higher diet quality and lower environmental impact, the likelihood of achieving nutrient EAR significantly increased as variety of food choice in the 'Fresh meat and alternatives' food group increased (P < 0·001). Variety score and number of serves were also correlated (r = 0·52, P < 0·001) which is relevant since most diets did not meet the recommended minimum number of serves for this food group. CONCLUSIONS: Greater variety within the 'Fresh meat and alternatives' food group is beneficial to meeting EAR and lower environmental impact diets can include three or more selections including foods of animal origin.

The role of dairy foods in lower greenhouse gas emission and higher diet quality dietary patterns.

PURPOSE: There is conflicting advice about the inclusion of dairy foods in a lower greenhouse gas (GHG) emission dietary pattern. Our purpose was to assess the prevalence of dairy food intake among higher diet quality and lower GHG emission diets in Australia and within these diets assess the association between level of dairy food intake and adequate intake of a broad range of nutrients. METHODS: Dietary intake data collected using a 24-h recall process were sourced from the most recent Australian Health Survey. Diet quality was assessed by level of compliance with the food group-based Australian Dietary Guidelines. A subgroup of 1732 adult (19 years and above) daily diets was identified having higher diet quality score and lower GHG emissions (HQLE). Intake of core dairy foods (milk, cheese, yoghurt) was assessed and nutrient profiling was undertaken for 42 macro- and micronutrients. RESULTS: The HQLE subgroup had 37% higher diet quality score and 43% lower GHG emissions than the average Australian adult diet (P < 0.05). Intake of dairy foods was very common (90% of HQLE diets) and greatly exceeded the intake of non-dairy alternatives (1.53 serves compared to 0.04 serves). HQLE daily diets in the highest tertile of dairy food intake were more likely to achieve the recommended intake of a wide range of nutrients, including calcium, protein, riboflavin, vitamin B12, folate, phosphorous, magnesium, iodine and potassium compared to other HQLE daily diets. CONCLUSION: Core dairy foods have an important role for achieving adequate nutrient intakes in a healthy and lower GHG emission dietary pattern in Australia.

An assessment of the water use associated with Australian diets using a planetary boundary framework.

OBJECTIVE: Agriculture accounts for around 70 % of global freshwater withdrawals. As such, the food system has been identified as a critical intervention point to address water scarcity. Various studies have identified dietary patterns that contribute less to water scarcity. However, it is unclear what level of reduction is necessary to be considered sustainable. The pursuit of unnecessarily aggressive reductions could limit dietary diversity. Our objective was to assess the sustainability of water use supporting Australian dietary habits and the adequacy of current dietary guidelines. DESIGN: Dietary intake data were obtained from the National Nutrition and Physical Activity component of the Australian Health Survey. For each individual daily diet, the water scarcity footprint was quantified, following ISO14046:2014, as well as a diet quality score. Water scarcity footprint results were compared with the planetary boundary for freshwater use downscaled to the level of an individual diet. SETTING: Australia. PARTICIPANTS: 9341 adults participating in the Australian Health Survey. RESULTS: Dietary water scarcity footprints averaged 432·6 L-eq (95 % CI 432·5, 432·8), less than the 695 litres/person per d available to support the current global population of 7·8 billion, and the 603 litres/person per d available for a future population of 9 billion. Diets based on the Australian Dietary Guidelines required 521 L-eq/d, or 379 L-eq/d with lower water scarcity footprint food choices. CONCLUSIONS: Diets based on the Australian Dietary Guidelines were found to be within the freshwater planetary boundary. What is needed in Australia is greater compliance with dietary guidelines.

From Water-Use to Water-Scarcity Footprinting in Environmentally Extended Input-Output Analysis.

Environmentally extended input-output analysis (EEIOA) supports environmental policy by quantifying how demand for goods and services leads to resource use and emissions across the economy. However, some types of resource use and emissions require spatially explicit impact assessment for meaningful interpretation, which is not possible in conventional EEIOA. For example, water use in locations of scarcity and of abundance are not environmentally equivalent. Opportunities for spatially explicit impact assessment in conventional EEIOA are limited because official input-output tables tend to be produced at the scale of political units, which are not usually well-aligned with environmentally relevant spatial units. In this study, spatially explicit water-scarcity factors and a spatially disaggregated Australian water-use account were used to develop water-scarcity extensions that were coupled with a multiregional input-output model (MRIO). The results link demand for agricultural commodities to the problem of water scarcity in Australia and globally. Important differences were observed between the water-use and water-scarcity footprint results as well as the relative importance of direct and indirect water use, with significant implications for sustainable production and consumption-related policies. The approach presented here is suggested as a feasible general approach for incorporating spatially explicit impact assessments in EEIOA.

Diet Quality and Water Scarcity: Evidence from a Large Australian Population Health Survey.

There is widespread interest in dietary strategies that lower environmental impacts. However, various forms of malnutrition are also widely prevalent. In a first study of its kind, we quantify the water-scarcity footprint and diet quality score of a large (>9000) population of self-selected adult daily diets. Here, we show that excessive consumption of discretionary foods-i.e., energy-dense and nutrient-poor foods high in saturated fat, added sugars and salt, and alcohol-contributes up to 36% of the water-scarcity impacts and is the primary factor differentiating healthier diets with lower water-scarcity footprint from poorer quality diets with higher water-scarcity footprint. For core food groups (fruits, vegetables, etc.), large differences in water-scarcity footprint existed between individual foods, making difficult the amendment of dietary guidelines for water-scarcity impact reduction. Very large reductions in dietary water-scarcity footprint are possible, but likely best achieved though technological change, product reformulation and procurement strategies in the agricultural and food industries.

Rethinking environmental stress from the perspective of an integrated environmental footprint: Application in the Beijing industry sector.

Individual footprint indicators are limited in that they usually only address one specific environmental aspect. For this reason, assessments involving multiple footprint indicators are preferred. However, the interpretation of a profile of footprint indicators can be difficult as the relative importance of the different footprint results is not readily discerned by decision-makers. In this study, a time series (1997-2012) of carbon, water and land footprints was calculated for industry sectors in the Beijing region using input-output analysis. An integrated environmental footprint (IEF) was subsequently developed using normalization and entropy weighting. The results show that steep increases in environmental footprint have accompanied Beijing's rapid economic development. In 2012, the Primary Industry had the largest IEF (8.32); however, the Secondary Industry had the greatest increase over the study period, from 0.19 to 6.37. For the Primary Industry, the greatest contribution to the IEF came from the land footprint. For the Secondary and Tertiary Industries, the water footprint was most important. Using the IEF, industry sectors with low resource utilization efficiency and high greenhouse gas emissions intensity can be identified. As such, the IEF can help to inform about industry sectors which should be given priority for modernization as well as the particular footprints that require priority attention in each sector. The IEF can also be helpful in identifying industry sectors that could be encouraged to expand within the Beijing region as they are especially efficient in terms of value adding relative to IEF. Other industries, over time, may be better located in other regions that do not face the same environmental pressures as Beijing.

Dietary Strategies to Reduce Environmental Impact: A Critical Review of the Evidence Base.

The food system is a major source of environmental impact, and dietary change has been recommended as an important and necessary strategy to reduce this impact. However, assessing the environmental performance of diets is complex due to the many types of foods eaten and the diversity of agricultural production systems and local environmental settings. To assess the state of science and identify knowledge gaps, an integrative review of the broad topic of environment and diet was undertaken, with particular focus on the completeness of coverage of environmental concerns and the metrics used. Compared with the 14 discrete environmental areas of concern identified in the United Nations Sustainable Development Goals, the located journal literature mainly addressed greenhouse gas (GHG) emissions and, to a lesser extent, land and water use. Some relevant concerns were rarely addressed or not addressed at all. In the case of GHG emissions, changes in land use and soil carbon stocks were seldom considered. This represents a disconnect between the science informing strategic climate action in the agricultural sector and the science informing public health nutrition. In the case of land and water use, few studies used metrics that are appropriate in a life-cycle context. Some metrics produce inherently biased results, which misinform about environmental impact. The limited evidence generally points to recommended diets having lower environmental impacts than typical diets, although not in every case. This is largely explained by the overconsumption of food energy associated with average diets, which is also a major driver of obesity. A shared-knowledge framework is identified as being needed to guide future research on this topic. Until the evidence base becomes more complete, commentators on sustainable diets should not be quick to assume that a dietary strategy to reduce overall environmental impact can be readily defined or recommended.