Black Soldier Flies Are Not an Ideal Solution for Global Food Waste

In the drive to make food production more sustainable, much attention has centered on solutions for global food waste. Researchers and multilateral organizations have characterized black soldier flies as a potential solution to combat food waste and reduce the high environmental impacts of animal agriculture. Proponents contend that black soldier fly larvae can consume almost any type of organic waste and become a protein source for animals and people while leaving residues valuable as agricultural fertilizer.[1] In particular, black soldier flies are touted as a large-scale replacement for soy meal used in farmed animal feed, the production of which drives global deforestation and climate change. But is black soldier fly farming truly the most impactful food waste solution?

Food systems experts have cautioned that the environmental sustainability gains offered by insect farming are unclear at best and illusory at worst.[2] Black soldier fly production is strongly tied to industrial animal agriculture, one of the most exploitative and environmentally damaging global industries. By greatly increasing the number of beings harmed by the global food supply chain, large-scale production of black soldier flies would also raise significant ethical questions at unprecedented scales.

Despite these myriad concerns, black soldier flies are attracting millions of dollars of private and public investment as an environmentally friendly food waste solution. Buoyed by food waste management hopes, the global black soldier fly market is expected to grow by one-third to $3.4 billion by 2030. This influx of support runs the risk of drowning out calls for systemic food system transformation with greater potential to deliver co-benefits for food waste reduction, human wellbeing, animal wellbeing, and environmental protection.

As a potential solution for food waste, black soldier fly farming presents uncertain benefits and significant concerns. Barriers include a mismatch between the black soldier fly industry and the global food waste problems most in need of solutions, structural challenges and regulatory gaps limiting the benefits of fly production, and important tradeoffs between fly farming and more systemic solutions to food waste.

Turning Trash into Treasure, But at What Scale?

Food waste is a complex global phenomenon with regional variation in characteristics and contributing factors. Although food waste happens to some degree in all production and consumption contexts worldwide, data collection varies greatly from place to place, and measurements at national and international levels rely on extrapolations and estimates. An estimated 13.8[3]15.3%[4] of global food production goes to waste before it ever reaches a consumer, left unharvested in farm fields, or wasted during post-harvest transport, processing, and food manufacturing. This food wasted in agricultural supply chains is typically referred to as “food loss,” although the term hides[i] the role that human decisions play in perpetuating food waste at the farm level.[5] An additional 17% of global food production goes to waste at the consumption end of the supply chain, representing 931 million tonnes (over two trillion pounds) of edible food wasted globally every year. Sixty-one percent of this waste comes from households, 26% from food service, and 13% from grocery retail.[6] Together the production and decomposition of this wasted food causes 8–10% of the world’s greenhouse gas emissions.

Considering the immense scale and significant environmental impacts of global food loss and waste, interventions that can convert unused food into useful products seem especially attractive. With their voracious appetites for organic matter inedible by humans, black soldier flies have been suggested as a way to turn environmentally costly food waste into usable protein, providing multiple benefits. For example, a new three-year international research project led by the National University of Singapore aims to use black soldier flies to facilitate fully circular food production in urban contexts, solving the twin problems of high emissions from incineration of local food waste and national reliance on imported fertilizer and animal feed.

While black soldier fly farming may provide attractively bundled solutions in specific local or regional contexts as part of such initiatives, food waste is a global environmental problem situated in the context of a global food system in need of deeper transformation. For black soldier flies to be a viable solution for global food waste, their contribution to food waste management would have to outweigh any negative impacts on the global food system and justify displacing attention and resources from alternative interventions.

Black Soldier Production Entrenches Animal Agriculture

Currently, black soldier flies are only produced at scale to feed farmed and companion animals within the dominant industrial agricultural system. Although some nutrition experts argue that black soldier fly protein would also make a healthful and more environmentally sustainable source of dietary protein for humans, particularly as an alternative to ruminant meat, the animal feed and aquaculture sectors remain the primary area of projected future growth for the black soldier fly market.

Energy and investment poured into black soldier flies as a potential solution to food waste rest on the use of fly protein as feed for farmed animals. Proponents frame waste-to-protein as an environmentally sustainable circular food system innovation. Such framings prioritize existing food production and consumption norms, bypassing a true accounting of the harms—human, animal, and environmental—of continuing industrial animal agriculture, including harm to human health, exploitation of food system workers, animal suffering, high greenhouse gas emissions, and serious air and water pollution.[7] By propping up and entrenching industrial animal agriculture, insect protein would likely worsen the broader environmental and societal problems of intensive animal farming.

Not all Wasted Food is Useless

Research promoting black soldier flies often characterizes fly farming as a simple solution to the static problem of food waste, hiding the true complexity of the issue. At present, there is a fundamental mismatch between the insect farming industry’s practices and the most significant problems of global food waste. At the root of this mismatch are questions about how to define food waste and tradeoffs between alternative uses for agricultural and food manufacturing byproducts.

At present, black soldier flies and other farmed insects are rarely fed consumer-level food waste, where the bulk of food waste occurs. Producers of black soldier flies often source a single byproduct of food or biofuel production, such as spent brewery grains or cornmeal. Such byproducts have potential as human food sources, for example, by making bread from spent brewer’s grain or flour from soy fibers leftover from making tofu and soy milk. Thus, these byproducts may not rightly be considered food waste, and diverting them as food for black soldier flies presents important tradeoffs.

Additionally, agricultural byproducts such as spent brewers’ grains already have a use as feed for intensively farmed animals. Since black soldier flies are primarily farmed as a replacement for soy protein in animal feed, raising them on food byproducts that would otherwise feed farmed animals is of questionable value for resource efficiency. At a minimum, diverting already useful food manufacturing byproducts as black soldier fly feed fails to address the most significant sources of global food waste.

Feasibility and Suitability Concerns

In the rare cases where insect farming does use consumer-level food waste that would otherwise go to landfill or decomposition, not all waste streams are suitable or efficient as insect feed. The efficiency with which insect larvae can convert organic material into insect biomass varies considerably depending on the composition of the source.[8] Within current industrial food supply chains, industrial fly protein producers will face financial pressure to find the most cost-efficient feed source for flies rather than the food waste streams most in need of solutions. Research into best diets for black soldier fly larvae has highlighted the suitability of feedstocks such as biofuel refinery waste,[9] making insect farming a potential contributor to environmentally damaging biofuel production. Such risks could undermine potential environmental gains from food waste reduction.

Feeding black soldier flies on consumer-level food waste also has unclear environmental benefits. A 2019 review of environmental impact measurements comparing black soldier fly feed sources indicated that feeding farmed insects on food manufacturing byproducts typically has larger environmental impacts than the soy meal and fish meal that insect protein is meant to replace. Plant-based protein sources, rather than the mixed sources in consumer waste, still have the lowest environmental impacts.[10]

There are additional questions about the infrastructure and systems needed to repurpose consumer and retail food waste as black soldier fly feedstock. Although black soldier flies can eat many types of organic waste, aligning existing food loss and waste streams with fly farming is less than straightforward. The same regional heterogeneity and lack of central management that make food loss and waste difficult to measure within agricultural supply chains also make a large-scale transition to waste processing by black soldier flies a significant challenge. Taking food waste conversion by flies from controlled experimental conditions to real-world applications at scale would require global population centers to transition to organic waste recovery systems and practices capable of effectively diverting significant quantities of wasted food under conditions suitable for raising flies and their larvae. Such an immense food system reorganization should be weighed against other interventions and considered in the context of larger food system transformations.

Better Solutions for Food Waste

Focusing on solving the problem of food waste at the post-consumer level also ignores more impactful interventions at earlier steps of the food supply chain. Myriad factors contribute to food loss and waste between farm and fork. Driving forces include artificially low commodity food prices that sometimes make it financially sensible to plow harvestable food back into the earth, lack of access to refrigeration infrastructure during harvest and transport, convenience food purchasing lifestyles, the influence of food marketing, and package sizes that do not match up with typical use. Some causes are inevitable—such as crop damage due to extreme weather events—but others result from structures of the industrial food system that are linked to a range of negative impacts in addition to food waste. Investing in black soldier flies as a singular solution for end-stage food waste could overshadow opportunities to avoid waste by implementing deeper, systemic food system reforms.

US nonprofit ReFED has produced a roadmap to halving food waste in the US by 2030, in line with the United Nations Sustainable Development Goals. Solutions with the highest potential to cut food loss and waste include avoiding farm-level food losses caused by mismatched supply and demand, reducing portion sizes at food retail, and expanding centralized composting programs to process consumer waste.[11] Preventing waste before it starts has the added environmental benefit of reducing greenhouse gas emissions and air and water pollution generated during the production of food that ends up as waste. Composting offers scalable solutions for kitchen waste that can be implemented within existing waste management streams. In less wealthy countries that struggle with high rates of malnutrition, food manufacturing byproducts and some sources of food waste may also represent possible sources of nutrition for local populations.[12]

If black soldier fly production creates new markets for agricultural byproducts and circular food waste processing tied to industrial animal farming, tradeoffs will become increasingly evident between fly farming and potentially more resource-wise strategies including food waste prevention and alternative uses of waste products.

Regulatory Gaps

In addition to fundamental resource efficiency and feasibility questions, there are also regulatory restrictions and gaps that make it difficult to view insect farming as a ready solution for consumer food waste. Food safety regulations in the US and EU govern what types of feed can be given to farmed animals. EU food law currently only allows vegetal matter to be used in farmed animal feedstocks, meaning that much consumer food waste is prohibited. Regulation specific to farmed insects is lacking across both high-income and lower-income nations.[13] Additional regulatory complications arise when farmed insects are intended for use as human food, as some researchers propose. Incomplete and restrictive regulation of farmed insect diets makes the future of insect farming as a food waste solution yet more uncertain.

The choice of feed for farmed insects depends on factors such as insect growth rate, the nutritional profile of the insect meal produced, and the cost of feedstock.[14] Even if future regulation addresses safety concerns and allows a wider variety of food waste to be fed to farmed insects, not all insect protein producers would necessarily choose the feed sources with the lowest environmental impacts or the greatest potential for addressing food waste. Maximizing feed conversion efficiency for farmed insects within the confines of existing regulation may also lead to additional environmental impacts that swamp environmental benefits.

Ethical Concerns

One important element often left out of discussions of insect farming industry growth and the food waste reduction potential of circular economy initiatives is the ethical concern of raising—and killing—large numbers of insects during the production of animal feed and other industrial applications of insect protein. Substituting plant protein inputs such as soy meal with black soldier fly meal in farmed animal feed exponentially expands the number of animals impacted by animal agriculture. Supplanting systemic food waste prevention measures or existing end-stage measures such as centralized composting by utilizing insects to break down consumer food waste would create a system reliant on untold numbers of additional insect lives that would be sacrificed in the production of industrial commodities.

Insects might well be sentient and capable of feeling pain and distress.[15] However, insect protein production typically relies on larvae, and it is not yet known whether larvae have the same neural capacity. In the absence of strong evidence to the contrary, avoiding intentional harm to larvae or adult flies is the most ethical course of action. Some scholarship addressing processing methods for farmed black soldier flies suggests applying the precautionary principle to minimize pain and discomfort for insects during slaughter and to ensure that slaughter is as quick as possible.[16] However, research by Rethink Priorities suggests that the welfare improvement from supposedly more humane ways of killing farmed insects is uncertain and that methods which may be officially considered humane for other species of farmed animals may not be practical for insects. Despite growing commercial interest in black soldier flies, researchers note that little is still known about their biology,[17] making it difficult to resolve ethical concerns.

Finally, farmed insects are very sensitive to temperature, light, and humidity and can suffer from disease and pre-slaughter mortality. Rethink Priorities found that moldy food waste, changes in humidity, and crowded conditions can spread disease among insects. Cost-saving measures on insect farms may also have welfare impacts. For instance, the researchers found that though insects have sensitive circadian rhythms, black soldier flies are raised on some farms “in total darkness to reduce energy costs and maximize yield.”

The ethical implications of insect farming do not end with the lives of the insects themselves. Because the vast majority of current insect production is processed into protein and fat for farmed animal feed stocks, insect farming directly props up the human and non-human suffering inherent in industrial animal agriculture. Feeding insects to farmed animals does nothing to improve the significant animal welfare harms found in the production of animal proteins for human consumption while greatly increasing the number of beings harmed by intensive animal farming.

Even if black soldier flies and other insects turn out not to be sentient, farming them may not be an ethical decision. As philosopher Jeff Sebo has said in relation to eating bivalves like mussels, which seem to lack sentience, “There are a lot of reasons to eat plant-based foods instead that go beyond the direct welfare impacts. We want to be encouraging people to frame animals as not to be eaten rather than get into the psychologically more complicated territory of labeling some animals as to be eaten, but other animals as not to be eaten.”

Black Soldier Flies Cannot Deliver Systemic Transformation

The industrial food system requires transformation to be fit for purpose in a future marked by rising human population and climate instability. Industrial food production is designed to prioritize high agricultural yields and maximize agribusiness profit, disregarding a long list of harmful impacts on people, animals, and the environment, including the production of waste. The same supply chain structures and constraints on consumer choice that serve the profit interests of agribusiness are at the heart of the problem of food loss and waste and must also be at the heart of its solutions.

Food waste reduction has been a popular rallying cry for many, in part because food waste has no proponents. However, wide acceptance and multilateral prioritization of the problem have not translated into collective support for systemic change compatible with achieving broad-based public good. The supply chain structures that create waste do have proponents, even if waste itself does not. Black soldier flies’ ability to turn byproducts of little value into monetizable inputs for industrial animal farming is immensely attractive to those invested in maintaining the status quo of the highly exploitative and unequal industrial food system precisely because it erases the imperative to pursue deeper reforms. Attention focused on black soldier fly waste management is attention diverted from establishing a new food production paradigm that benefits a wide range of stakeholders and the environment.

While food waste is a serious global issue, failure to consider food waste alongside its systemic causes stalls the food system transformation movement and leaves solutions with greater shared benefits unexplored. Deeper solutions exist that can deliver food waste reduction alongside benefits for communities, animals, and environments. Transformative solutions include ending intensive production of farmed animals, empowering food system workers and rural farming communities, shifting to sustainable agricultural methods, and expanding access to healthy food.


The idea of turning the seemingly intractable problem of food waste into an environmentally friendly protein source for people and farmed animals has clear allure for commercial interests and governments but belies the many uncertainties and risks of black soldier fly production. If buoyed by the search for solutions for food waste, fly farming could stand in the way of deeper food system transformation by further entrenching exploitative and environmentally damaging industrial animal agriculture and diverting resources away from systemic solutions to food waste.

The relative underdevelopment of policy and legislation surrounding insect farming presents an important opportunity for policymakers, multilateral agencies, and investors to compare the potential environmental and food waste benefits of insect farming against systemic food system solutions. It is also a chance for stakeholders at all levels of the food system to reconsider humanity’s relationship with animals and to question whether it is wise to exploit yet more animals to improve the inefficiencies of a food system already in need of deep transformation.

[i] In their report “Driven to Waste”, the World Wildlife Fund UK explains that the term “food loss” implies there is no human error or decision that leads to the food being wasted. WWF-UK argues that food waste is a more appropriate term as “there are a multitude of human factors (conscious decisions or otherwise) that drive food waste at farm level and elsewhere within the supply chain.”

[1] Shikha Ojha, Sara Bußler, and Oliver K. Schlüter, “Food Waste Valorisation and Circular Economy Concepts in Insect Production and Processing,” Waste Management 118 (December 1, 2020): 600–609,

[2] Lewis Bollard, “The Promise and Perils of Insect Farming” (San Francisco, USA: Open Philanthropy, August 22, 2021),

[3] FAO, ed., State of Food and Agriculture, Moving Forward on Food Loss and Waste Reduction 2019 (Rome: Food and Agriculture Organization of the United Nations, 2019).

[4] “Driven to Waste: The Global Impact of Food Loss and Waste on Farms” (Woking: WWF-UK, 2021),

[5] See endnote 4.

[6] Food Waste Index Report 2021 (Nairobi: United Nations Environment Program, 2021),

[7] Emmanuelle Lavaine, Philippe Majerus, and Nicolas Treich, “Health, Air Pollution, and Animal Agriculture,” Review of Agricultural, Food and Environmental Studies 101, no. 4 (December 1, 2020): 517–28,

[8] G. Bosch et al., “Conversion of Organic Resources by Black Soldier Fly Larvae: Legislation, Efficiency and Environmental Impact,” Journal of Cleaner Production 222 (June 10, 2019): 355–63,

[9] Longyu Zheng et al., “Double the Biodiesel Yield: Rearing Black Soldier Fly Larvae, Hermetia Illucens, on Solid Residual Fraction of Restaurant Waste after Grease Extraction for Biodiesel Production,” Renewable Energy 41 (May 1, 2012): 75–79,

[10] Sergiy Smetana, Eric Schmitt, Alexander Mathys, “Sustainable use of Hermetia illucens insect biomass for feed and food: Attributional and consequential life cycle assessment,” Resources, Conservation and Recycling, Volume 144 (2019): 285-296,

[11] Peter Re, “Roadmap to 2030: Reducing U.S. Food Waste by 50% and the ReFED Insights Engine At-A-Glance” (ReFED, February 2021),

[12] Cristian Torres-León et al., “Food Waste and Byproducts: An Opportunity to Minimize Malnutrition and Hunger in Developing Countries,” Frontiers in Sustainable Food Systems 2 (2018),

[13] S. Alagappan et al., “Legislative Landscape of Black Soldier Fly (Hermetia Illucens) as Feed,” Journal of Insects as Food and Feed 8, no. 4 (April 8, 2022): 343–55,

[14] Karol Barragán-Fonseca, Julián Pineda-Mejia, Marcel Dicke, Joop J A van Loon. “Performance of the Black Soldier Fly (Diptera: Stratiomyidae) on Vegetable Residue-Based Diets Formulated Based on Protein and Carbohydrate Contents,” Journal of Economic Entomology, Volume 111, Issue 6, December 2018, Pages 2676–2683,

[15] Matilda Gibbons, Sajedeh Sarlak and Lars Chittka “Descending control of nociception in insects?” Proceedings of the Royal Society B: Biological Sciences, 06 July 2022

[16] Jennifer Larouche, “Processing Methods for the Black Soldier Fly (Hermetia Illucens) Larvae : From Feed Withdrawal Periods to Killing Methods,” 2019,

[17] Daniele Bruno et al., “The Digestive System of the Adult Hermetia Illucens (Diptera: Stratiomyidae): Morphological Features and Functional Properties,” Cell and Tissue Research 378, no. 2 (November 2019): 221–38,

About the author

Stray Dog Institute

To cultivate dignity, justice, and sustainability in the food system, Stray Dog Institute provides nonprofit allies with funding, strategic research, and opportunities for collaboration. Together, we hope to build a more compassionate world for people, animals, and the environment.

About the Author

To cultivate dignity, justice, and sustainability in the food system, Stray Dog Institute provides nonprofit allies with funding, strategic research, and opportunities for collaboration. Together, we hope to build a more compassionate world for people, animals, and the environment.

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