Environmental performance of blue foods.

Fish and other aquatic foods (blue foods) present an opportunity for more sustainable diets1,2. Yet comprehensive comparison has been limited due to sparse inclusion of blue foods in environmental impact studies3,4 relative to the vast diversity of production5. Here we provide standardized estimates of greenhouse gas, nitrogen, phosphorus, freshwater and land stressors for species groups covering nearly three quarters of global production. We find that across all blue foods, farmed bivalves and seaweeds generate the lowest stressors. Capture fisheries predominantly generate greenhouse gas emissions, with small pelagic fishes generating lower emissions than all fed aquaculture, but flatfish and crustaceans generating the highest. Among farmed finfish and crustaceans, silver and bighead carps have the lowest greenhouse gas, nitrogen and phosphorus emissions, but highest water use, while farmed salmon and trout use the least land and water. Finally, we model intervention scenarios and find improving feed conversion ratios reduces stressors across all fed groups, increasing fish yield reduces land and water use by up to half, and optimizing gears reduces capture fishery emissions by more than half for some groups. Collectively, our analysis identifies high-performing blue foods, highlights opportunities to improve environmental performance, advances data-poor environmental assessments, and informs sustainable diets.

Aquatic foods to nourish nations.

Despite contributing to healthy diets for billions of people, aquatic foods are often undervalued as a nutritional solution because their diversity is often reduced to the protein and energy value of a single food type ('seafood' or 'fish')1-4. Here we create a cohesive model that unites terrestrial foods with nearly 3,000 taxa of aquatic foods to understand the future impact of aquatic foods on human nutrition. We project two plausible futures to 2030: a baseline scenario with moderate growth in aquatic animal-source food (AASF) production, and a high-production scenario with a 15-million-tonne increased supply of AASFs over the business-as-usual scenario in 2030, driven largely by investment and innovation in aquaculture production. By comparing changes in AASF consumption between the scenarios, we elucidate geographic and demographic vulnerabilities and estimate health impacts from diet-related causes. Globally, we find that a high-production scenario will decrease AASF prices by 26% and increase their consumption, thereby reducing the consumption of red and processed meats that can lead to diet-related non-communicable diseases5,6 while also preventing approximately 166 million cases of inadequate micronutrient intake. This finding provides a broad evidentiary basis for policy makers and development stakeholders to capitalize on the potential of aquatic foods to reduce food and nutrition insecurity and tackle malnutrition in all its forms.

Photovoltaic-driven microbial protein production can use land and sunlight more efficiently than conventional crops.

Population growth and changes in dietary patterns place an ever-growing pressure on the environment. Feeding the world within sustainable boundaries therefore requires revolutionizing the way we harness natural resources. Microbial biomass can be cultivated to yield protein-rich feed and food supplements, collectively termed single-cell protein (SCP). Yet, we still lack a quantitative comparison between traditional agriculture and photovoltaic-driven SCP systems in terms of land use and energetic efficiency. Here, we analyze the energetic efficiency of harnessing solar energy to produce SCP from air and water. Our model includes photovoltaic electricity generation, direct air capture of carbon dioxide, electrosynthesis of an electron donor and/or carbon source for microbial growth (hydrogen, formate, or methanol), microbial cultivation, and the processing of biomass and proteins. We show that, per unit of land, SCP production can reach an over 10-fold higher protein yield and at least twice the caloric yield compared with any staple crop. Altogether, this quantitative analysis offers an assessment of the future potential of photovoltaic-driven microbial foods to supplement conventional agricultural production and support resource-efficient protein supply on a global scale.

Digital food sharing and food insecurity in the COVID-19 era.

Sharing food surplus via the digital sharing economy is often discussed as a promising strategy to reduce food waste and mitigate food insecurity at the same time. Yet if and how the global pandemic has affected digital food sharing are not yet well understood. Leveraging a comprehensive dataset covering over 1.8 million food exchanges facilitated by a popular peer-to-peer food sharing platform, we find that UK activity levels not only rose during the Covid-19 pandemic, but outperformed projections. A potential explanation for this growth might be the rise of food insecurity during the pandemic. Yet examining the sociodemographic characteristics of platform users, average user activity and food exchanges before and during the pandemic, we find no compelling evidence that the platform's pandemic-era growth results from a large influx of food insecure users. Instead, we poist that the growth in digital food sharing relates to lifestyle changes potentially triggered by the pandemic.

The SHED Index: a tool for assessing a Sustainable HEalthy Diet.

PURPOSE: Promoting sustainable diets through sustainable food choices is essential for achieving the sustainable development goals set by the United Nations. Establishing a practical tool that can measure and score sustainable and healthy eating is highly important. METHODS: We established a 30-item questionnaire to evaluate sustainable-dietary consumption. Based on the literature and a multidisciplinary advisory panel, the questionnaire was computed by principal component analysis, yielding the Sustainable-HEalthy-Diet (SHED) Index. A rigorous multi-stage process included validation in training-verification sets, across recycling efforts, as an indicator of environmental commitment; and validation across the proportion of animal-protein consumption, as an indicator of adherence to a sustainable and healthy dietary-pattern. The EAT-Lancet reference-diet and the Mediterranean-Diet-score were used to investigate the construct validity of the SHED Index score. Reliability was assessed with a test-retest sample. RESULTS: Three-hundred-forty-eight men and women, aged 20-45 years, completed both the SHED Index questionnaire and a validated Food-Frequency-Questionnaire. Increased dietary animal-protein intake was associated with a lower SHED Index total score (p < 0.001). Higher recycling efforts were associated with a higher total SHED Index score (p < 0.001). A linear correlation was found between the SHED Index score and food-groups of the Eat-Lancet-reference diet. A significant correlation was found between the Mediterranean-Diet-score and the SHED Index score (r = 0.575, p < 0.001). The SHED Index score revealed high reliability in test-retest, high validity in training and verification sets, and internal consistency. CONCLUSION: We developed the SHED Index score, a simple, practical tool, for measuring healthy and sustainable individual-diets. The score reflects the nutritional, environmental and sociocultural aspects of sustainable diets; and provides a tangible tool to be used in intervention studies and in daily practice.

The opportunity cost of animal based diets exceeds all food losses.

Food loss is widely recognized as undermining food security and environmental sustainability. However, consumption of resource-intensive food items instead of more efficient, equally nutritious alternatives can also be considered as an effective food loss. Here we define and quantify these opportunity food losses as the food loss associated with consuming resource-intensive animal-based items instead of plant-based alternatives which are nutritionally comparable, e.g., in terms of protein content. We consider replacements that minimize cropland use for each of the main US animal-based food categories. We find that although the characteristic conventional retail-to-consumer food losses are ≈30% for plant and animal products, the opportunity food losses of beef, pork, dairy, poultry, and eggs are 96%, 90%, 75%, 50%, and 40%, respectively. This arises because plant-based replacement diets can produce 20-fold and twofold more nutritionally similar food per cropland than beef and eggs, the most and least resource-intensive animal categories, respectively. Although conventional and opportunity food losses are both targets for improvement, the high opportunity food losses highlight the large potential savings beyond conventionally defined food losses. Concurrently replacing all animal-based items in the US diet with plant-based alternatives will add enough food to feed, in full, 350 million additional people, well above the expected benefits of eliminating all supply chain food waste. These results highlight the importance of dietary shifts to improving food availability and security.

Land, irrigation water, greenhouse gas, and reactive nitrogen burdens of meat, eggs, and dairy production in the United States.

Livestock production impacts air and water quality, ocean health, and greenhouse gas (GHG) emissions on regional to global scales and it is the largest use of land globally. Quantifying the environmental impacts of the various livestock categories, mostly arising from feed production, is thus a grand challenge of sustainability science. Here, we quantify land, irrigation water, and reactive nitrogen (Nr) impacts due to feed production, and recast published full life cycle GHG emission estimates, for each of the major animal-based categories in the US diet. Our calculations reveal that the environmental costs per consumed calorie of dairy, poultry, pork, and eggs are mutually comparable (to within a factor of 2), but strikingly lower than the impacts of beef. Beef production requires 28, 11, 5, and 6 times more land, irrigation water, GHG, and Nr, respectively, than the average of the other livestock categories. Preliminary analysis of three staple plant foods shows two- to sixfold lower land, GHG, and Nr requirements than those of the nonbeef animal-derived calories, whereas irrigation requirements are comparable. Our analysis is based on the best data currently available, but follow-up studies are necessary to improve parameter estimates and fill remaining knowledge gaps. Data imperfections notwithstanding, the key conclusion--that beef production demands about 1 order of magnitude more resources than alternative livestock categories--is robust under existing uncertainties. The study thus elucidates the multiple environmental benefits of potential, easy-to-implement dietary changes, and highlights the uniquely high resource demands of beef.

Environmentally Optimal, Nutritionally Aware Beef Replacement Plant-Based Diets.

Livestock farming incurs large and varied environmental burdens, dominated by beef. Replacing beef with resource efficient alternatives is thus potentially beneficial, but may conflict with nutritional considerations. Here we show that protein-equivalent plant based alternatives to the beef portion of the mean American diet are readily devisible, and offer mostly improved nutritional profile considering the full lipid profile, key vitamins, minerals, and micronutrients. We then show that replacement diets require on average only 10% of land, 4% of greenhouse gas (GHG) emissions, and 6% of reactive nitrogen (Nr) compared to what the replaced beef diet requires. Applied to 320 million Americans, the beef-to-plant shift can save 91 million cropland acres (and 770 million rangeland acres), 278 million metric ton CO2e, and 3.7 million metric ton Nr annually. These nationwide savings are 27%, 4%, and 32% of the respective national environmental burdens.

Exploring scenarios for the food system-zoonotic risk interface.

The unprecedented economic and health impacts of the COVID-19 pandemic have shown the global necessity of mitigating the underlying drivers of zoonotic spillover events, which occur at the human-wildlife and domesticated animal interface. Spillover events are associated to varying degrees with high habitat fragmentation, biodiversity loss through land use change, high livestock densities, agricultural inputs, and wildlife hunting-all facets of food systems. As such, the structure and characteristics of food systems can be considered key determinants of modern pandemic risks. This means that emerging infectious diseases should be more explicitly addressed in the discourse of food systems to mitigate the likelihood and impacts of spillover events. Here, we adopt a scenario framework to highlight the many connections among food systems, zoonotic diseases, and sustainability. We identify two overarching dimensions: the extent of land use for food production and the agricultural practices employed that shape four archetypal food systems, each with a distinct risk profile with respect to zoonotic spillovers and differing dimensions of sustainability. Prophylactic measures to curb the emergence of zoonotic diseases are therefore closely linked to diets and food policies. Future research directions should explore more closely how they impact the risk of spillover events.

Estimating national and subnational nutrient intake distributions of global diets.

BACKGROUND: Access to high-quality dietary intake data is central to many nutrition, epidemiology, economic, environmental, and policy applications. When data on individual nutrient intakes are available, they have not been consistently disaggregated by sex and age groups, and their parameters and full distributions are often not publicly available. OBJECTIVES: We sought to derive usual intake distributions for as many nutrients and population subgroups as possible, use these distributions to estimate nutrient intake inadequacy, compare these distributions and evaluate the implications of their shapes on the estimation of inadequacy, and make these distributions publicly available. METHODS: We compiled dietary data sets from 31 geographically diverse countries, modeled usual intake distributions for 32 micronutrients and 21 macronutrients, and disaggregated these distributions by sex and age groups. We compared the variability and skewness of the distributions and evaluated their similarity across countries, sex, and age groups. We estimated intake inadequacy for 16 nutrients based on a harmonized set of nutrient requirements and bioavailability estimates. Last, we created an R package-nutriR-to make these distributions freely available for users to apply in their own analyses. RESULTS: Usual intake distributions were rarely symmetric and differed widely in variability and skewness across nutrients and countries. Vitamin intake distributions were more variable and skewed and exhibited less similarity among countries than other nutrients. Inadequate intakes were high and geographically concentrated, as well as generally higher for females than males. We found that the shape of usual intake distributions strongly affects estimates of the prevalence of inadequate intakes. CONCLUSIONS: The shape of nutrient intake distributions differs based on nutrient and subgroup and strongly influences estimates of nutrient intake inadequacy. This research represents an important contribution to the availability and application of dietary intake data for diverse subpopulations around the world.

Social and environmental analysis of food waste abatement via the peer-to-peer sharing economy.

Reducing food waste is widely recognized as critical for improving resource efficiency and meeting the nutritional demand of a growing human population. Here we explore whether the sharing economy can provide meaningful assistance to reducing food waste in a relatively low-impact and environmentally-sound way. Analyzing 170,000 postings on a popular peer-to-peer food-sharing app, we find that over 19 months, 90t of food waste with an equivalent retail value of £0.7 million were collected by secondary consumers and diverted from disposal. An environmental analysis focused on Greater London reveals that these exchanges were responsible for avoiding emission of 87-156t of CO2eq. Our results indicate that most exchanges were among users associated with lower income yet higher levels of education. These findings, together with the high collection rates (60% on average) suggest that the sharing economy may offer powerful means for improving resource efficiency and reducing food waste.

Reorientation of aquaculture production systems can reduce environmental impacts and improve nutrition security in Bangladesh.

Aquatic foods are a critical source of human nutrition in many developing countries. As a result, declines in wild-caught fish landings threaten nutritionally vulnerable populations. Aquaculture presents an opportunity to meet local demand, but it also places pressure on natural resource inputs and causes a range of environmental impacts. Here, we examine whether current aquaculture systems in Bangladesh can be reoriented to address prevailing nutritional deficiencies while minimizing these environmental impacts. Current fish farming practices, even when optimized, cannot fully supply the same essential micronutrient densities of zinc, iron and calcium as wild-caught fish. However, when the proportion of highly nutrient-dense small indigenous fish species (SIS) was increased to at least 30% of the total output in any of the 14 aquaculture production systems analysed, these systems were able to meet or surpass the nutrient densities of average wild-capture fisheries. Extensive aquaculture systems that co-produce fish and rice had the lowest environmental burdens in six out of seven metrics examined when the composition of all aquaculture systems was modified to include 50% SIS. Nutrition-sensitive aquaculture that provides greater human health benefits and minimizes environmental impacts is a key societal challenge that requires targeted interventions and supportive policies.

Author Correction: Environmentally Optimal, Nutritionally Sound, Protein and Energy Conserving Plant Based Alternatives to U.S. Meat.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Environmentally Optimal, Nutritionally Sound, Protein and Energy Conserving Plant Based Alternatives to U.S. Meat.

Because meat is more resource intensive than vegetal protein sources, replacing it with efficient plant alternatives is potentially desirable, provided these alternatives prove nutritionally sound. We show that protein conserving plant alternatives to meat that rigorously satisfy key nutritional constraints while minimizing cropland, nitrogen fertilizer (Nr) and water use and greenhouse gas (GHG) emissions exist, and could improve public health. We develop a new methodology for identifying nutritional constraints whose satisfaction by plant eaters is challenging, disproportionately shaping the optimal diets, singling out energy, mass, monounsaturated fatty acids, vitamins B3,12 and D, choline, zinc, and selenium. By replacing meat with the devised plant alternatives-dominated by soy, green pepper, squash, buckwheat, and asparagus-Americans can collectively eliminate pastureland use while saving 35-50% of their diet related needs for cropland, Nr, and GHG emission, but increase their diet related irrigation needs by 15%. While widely replacing meat with plants is logistically and culturally challenging, few competing options offer comparable multidimensional resource use reduction.

Conceptualizing a Sustainable Food System in an Automated World: Toward a "Eudaimonian" Future.

The industrialized world has entered a new era of widespread automation, and although this may create long-term gains in economic productivity and wealth accumulation, many professions are expected to disappear during the ensuing shift, leading to potentially significant disruptions in labor markets and associated socioeconomic difficulties. Food production, like many other industrial sectors, has also undergone a century of mechanization, having moved toward increasingly large-scale monoculture production-especially in developed economies-with higher yields but detrimental environmental impacts on a global scale. Certain characteristics of the food sector and its products cast doubts on whether future automation will influence it in the same ways as in other sectors. We conceptualize a model of future food production within the socioeconomic conditions created by widespread automation. We ideate that despite immediate shocks to the economy, in the long run higher productivity can free up human activity to be channeled toward more interactive, skill-intensive food production systems, where communal efforts can reduce industrial reliance, diversify farming, and reconnect people to the biosphere-a realization of human well-being that resembles the classical philosophical ideal of Eudaimonia. We explore food production concepts, such as communal gardens and polyculture, and the economic conditions and institutions needed to underwrite them [e.g., a universal basic income (UBI)]. However, arguments can be raised as to why social-ecological systems would benefit from more labor-intensive food production. In this paper we: (1) discuss the current state of the food system and the need to reform it in light of its environmental and social impacts; (2) present automation as a lever that could move society toward more sustainable food production; (3) highlight the beneficial attributes of a Eudaimonian model; and (4) discuss the potential challenges to its implementation. Our purpose is to highlight a possible outcome that future research will need to refine and expand based on evidence and successful case studies. The ultimate aim is to promote a food system that can provide food security while staying within the safe operating space of planetary boundaries, produce more nutritious diets, enhance social capital, and reconnect communities with the biosphere.

A model for 'sustainable' US beef production.

Food production dominates land, water and fertilizer use and is a greenhouse gas source. In the United States, beef production is the main agricultural resource user overall, as well as per kcal or g of protein. Here, we offer a possible, non-unique, definition of 'sustainable' beef as that subsisting exclusively on grass and by-products, and quantify its expected US production as a function of pastureland use. Assuming today's pastureland characteristics, all of the pastureland that US beef currently use can sustainably deliver ≈45% of current production. Rewilding this pastureland's less productive half (≈135 million ha) can still deliver ≈43% of current beef production. In all considered scenarios, the ≈32 million ha of high-quality cropland that beef currently use are reallocated for plant-based food production. These plant items deliver 2- to 20-fold more calories and protein than the replaced beef and increase the delivery of protective nutrients, but deliver no B12. Increased deployment of rapid rotational grazing or grassland multi-purposing may increase beef production capacity.