Editor`s Note - Planetary Health Diets and Aquaculture
For aquaculture, resource constraints mean that production from existing land area must increase, a goal that is difficult without simultaneously increasing greenhouse gas emissions associated with greater energy use. For this, decarbonization of the world’s energy system must be accelerated.
In January, a report was issued with the title “Food in The Anthropocene: the EAT-Lancet Commission on healthy diets from sustainable food systems.” The report calls for nothing less than “a radical transformation of the global food system.” It cites a growing body of research that links healthy diets and environmental sustainability. The challenge is that “the global food system must operate within boundaries for human health and food production to ensure healthy diets from sustainable food systems for nearly 10 billion people by 2050.”
The report recommends a diet rich in plant-based foods and with fewer animal source foods. To boil the message of the report down to its essence, the recommendation is to eat twice as much plant-based foods and half as much animal source foods, especially red meat. Vegetables should make up half the diet. For wealthier countries like the US, with very high levels of red meat consumption, reducing animal-source foods in diets can greatly improve health outcomes and mitigate climate change.
The report states that current diets are unsustainable and are pushing the planet beyond the safe operating space of humanity. The current food system is not working well: about 795 million people do not have enough food and experience hunger, 2 billion are micronutrient deficient and 2.5 billion are overweight or obese. Agriculture accounts for 30 percent of total greenhouse gas emissions and animal production accounts for about ¾ of total agricultural greenhouse gas emissions. About half of all land in agriculture is used to produce ingredients in animal feeds. Production of animals, including fish, generally requires more resources and has greater environmental impacts than plant production.
The report states that changing the food system will require three approaches: shifting to planetary health diets, sustainable intensification of agriculture, and halving food waste. Most of the media attention has rightly been on the sustainable diet because such a profound shift in consumption patterns can provide greater environmental benefits than increasing agricultural productivity. The interest in so-called sustainable diets has coincided with greater interest in balanced or healthy diets such as vegetarian, flexitarian, Mediterranean and even pescatarian!
What is the role of fish in sustainable diets? Fish is a high-quality, easily digestible and nutrient-dense source of complete protein, with abundant vitamins, micronutrients, and minerals. Fish in diets can address the health effects of food or micronutrient insufficiency and those of obesity and heart disease associated with excess calorie consumption. Fish contributes about 17 percent to the supply of animal protein, with a greater share in low-income countries. Fish provides around 4.5 billion people with 20 percent of their animal protein and are the primary protein source for more than 1.3 billion people. The allowance of fish under the planetary health diet is a mere 28 g/d (1 oz) or 200 g/wk, equivalent to eating fish once or twice per week. The allotment of fish under the planetary health diet is half the current per capita consumption of around 20 kg/yr. This is discouraging news to those working in aquaculture and advocating for greater fish consumption.
It is difficult to conceive how such profound dietary shifts will take place given current trends. As incomes and standards of living have risen, the pattern has been for consumers to shift towards greater consumption of animal source protein, including fish. With prosperity and urbanization, diets have become much more Westernized, with more meat and less vegetable consumption. Of course, population increases on their own are important drivers of increased demand for animal source foods. Choosing what to eat is ultimately an individual decision, although it is strongly mediated by the prevailing food culture and national cuisine. Diets can shift if consumers become more aware, perceive a benefit of changing, or can change with minimum disruption. Changing social norms is also a powerful force for change. People can and do change their diets in response to awareness programs, popular culture and marketing programs.
However, the magnitude of the changes proposed in the EAT-Lancet report and the relatively short time available to achieve the goal of staying within planetary boundaries means that large-scale behavioral changes requires public health, agriculture and food policies that incentivize sustainable food choices and perhaps restrict or disincentivize consumption of less sustainable foods. It is difficult to envision this idealistic scenario in the world we live in, with a distinct lack of political will to move consumption in a more sustainable direction. Even though moving towards a diet that is good for health and good for the environment is an aspirational target, it is a worthy goal and aquaculture can do its part.
The second major target identified in the EAT-Lancet report was related to sustainable food production to reduce pressure on resources and ecosystem services. The report calls for sustainable intensification of agriculture with no use of new land, careful use of water resources, reduced emissions of greenhouse gases and nutrients that cause eutrophication, and guarding existing biodiversity. Sustainable intensification can be achieved by implementing better practices to close the yield gap, especially for carp ponds in Asia that have the greatest aggregate impact. Aquaculture researchers can help by developing and evaluating changes to production practices that mitigate environmental impacts.
For aquaculture, resource constraints mean that production from existing land area must increase, a goal that is difficult without simultaneously increasing greenhouse gas emissions associated with greater energy use. For this, decarbonization of the world’s energy system must be accelerated. One possibility is to shift animal production to a mix of species that are more efficient. Production of fish in aquaculture is a more efficient and less environmentally impactful form of animal production than that of most terrestrial livestock, especially beef. Policies that favor aquaculture over terrestrial livestock production should be promoted, especially where resources are limiting. Aquaculture can and must do its part to contribute to healthy diets and sustainable food production.