Nutrition Diet: Are flies considered proteins?

October 17, 2025 •

3 min read

Over two billion people worldwide consume insects, highlighting the growing practice of entomophagy. In this context, the question arises, are flies considered proteins? The answer, for specific farmed species, is a definitive yes, with some fly larvae boasting a higher protein content per dry weight than beef or chicken.

Quick Summary

An exploration of flies as a protein source for nutrition. Discusses the protein content of species like the Black Soldier Fly, comparing their nutritional profile and sustainability to traditional protein sources. Explores processing, potential risks, and future potential of insect-based diets.

Key Points

Fly larvae are a dense protein source: Species like the Black Soldier Fly can contain over 50% protein by dry weight, comparable to conventional meat.
Complete amino acid profile: Cultivated fly larvae contain all nine essential amino acids necessary for human nutrition.
High sustainability: Insect farming is more environmentally friendly, requiring less land, water, and feed than traditional livestock production.
Safety through processing: While wild flies can carry pathogens, commercially farmed flies are safe for consumption when properly processed through cooking or drying.
Allergy risk: Individuals with shellfish allergies should be cautious, as cross-reactivity with insect proteins is a known risk.
Overcoming cultural barriers: Innovative food products, such as protein powders and insect flour, are being developed to improve consumer acceptance.

The Surprising Truth: Flies as a Protein Source

While the thought of eating flies may evoke revulsion in many Western cultures, insects have been a staple food source for centuries in numerous societies around the globe. With the escalating global demand for sustainable protein, scientific interest in entomophagy—the human consumption of insects—has surged. Flies, often considered pests, are emerging as a viable and highly efficient protein alternative, particularly in their larval stage.

The Nutritional Powerhouse: Black Soldier Fly Larvae

Not all flies are created equal when it comes to nutrition. The most prominent example of a fly species cultivated for food and feed is the Black Soldier Fly (BSF) (Hermetia illucens). Unlike common houseflies that scavenge on unsanitary matter, BSF larvae are voracious eaters of organic waste, and when commercially farmed under controlled conditions, they represent a clean and sustainable protein source.

Nutritional Profile of Fly Larvae:

High-Quality Protein: BSF larvae can contain between 35% and 61% crude protein on a dry-matter basis, often containing all nine essential amino acids required by humans.
Healthy Fats: The larvae are also a source of healthy fats, including medium-chain fatty acids like lauric acid, which has antimicrobial properties.
Micronutrients: They provide essential minerals such as iron, zinc, magnesium, and calcium, as well as B vitamins.
Fiber (Chitin): The exoskeleton of flies contains chitin, a dietary fiber that has been linked to health benefits like lowering cholesterol.

Comparing Flies to Conventional Proteins

The case for insect protein is strengthened when comparing its production efficiency and nutritional output to conventional livestock. Insect farming is significantly more sustainable, requiring a fraction of the land, water, and feed to produce the same amount of protein.


Attribute	Black Soldier Fly Larvae (Dry Weight)	Beef (Lean, Raw)	Chicken (Skinless, Raw)
Protein Content (per 100g)	35-61g	~22.5g	~22.2g
Fat Content (per 100g)	7-42g	~8.7g	~2.6g
Feed Conversion Efficiency	High (Converts food to body mass very efficiently)	Low (Requires a large amount of feed)	Moderate
Land Use	Low (Vertical farming possible)	High (Pastures and cropland for feed)	Moderate
Greenhouse Gas Emissions	Low	High	Moderate
Water Requirements	Low	High	Moderate

Safety and Processing for Human Consumption

When considering insects like flies for human consumption, especially in regions unaccustomed to entomophagy, safety is paramount. Wild-caught flies pose a risk of contamination from pathogens, pesticides, or other environmental toxins. However, commercially farmed flies offer a safe alternative when processed correctly.

Key safety and processing considerations include:

Controlled Rearing: Insects raised in clean, controlled environments on approved feed substrates are free from the contaminants found in wild populations.
Proper Processing: Cooking, drying, or pulverizing insects into flour or protein powder effectively eliminates bacteria and other potential hazards.
Allergen Awareness: Individuals with shellfish allergies should exercise caution, as cross-reactivity due to similar proteins (like tropomyosin) can occur.

Overcoming the “Yuck” Factor

The biggest hurdle for widespread adoption of fly protein is consumer perception. To address this, many companies are developing insect-based products that are unrecognizable from their original form, such as protein powders for smoothies or flour for baked goods. This approach has shown greater consumer acceptance and helps normalize insects as a food source. As the environmental and nutritional benefits become more widely publicized, societal attitudes may shift, paving the way for insect protein to play a significant role in future food systems. For more detailed information on insect protein production, review this article from the National Institutes of Health.

Conclusion

In conclusion, certain farmed flies, notably the Black Soldier Fly, are indeed a highly nutritious and viable source of protein. Their exceptional protein content, coupled with a complete amino acid profile and a lower environmental footprint compared to traditional livestock, positions them as a promising food source for the future. While cultural norms present a barrier, innovative food processing and increased awareness of their sustainable benefits can help integrate these mini-livestock into modern diets, contributing to global food security and environmental sustainability.

Frequently Asked Questions

The most widely studied and farmed fly for protein is the Black Soldier Fly (Hermetia illucens), particularly its larvae. Other fly species, though not commonly farmed for food, also contain protein.

While accidentally swallowing a single fly is unlikely to cause harm due to your stomach's acid, it is generally considered unsanitary. Flies can carry bacteria like Shigella on their bodies from landing on unsanitary surfaces. Wild flies should not be intentionally consumed.

On a dry-matter basis, the larvae of farmed flies can contain a higher percentage of protein than beef. For example, BSF larvae can be 35-61% protein by dry weight, whereas lean beef is around 22.5% protein.

In addition to a complete amino acid profile, fly larvae are a good source of healthy fats, minerals like iron and zinc, and B vitamins. Their exoskeleton also contains dietary fiber in the form of chitin.

Fly farming requires significantly fewer resources—including land, water, and feed—compared to conventional livestock. This results in lower greenhouse gas emissions and a more sustainable food production process.

Yes. People with shellfish allergies are at higher risk of an allergic reaction to insect protein due to cross-reactivity with similar proteins, such as tropomyosin. Consulting a doctor is advised for those with existing allergies.

To make them safe and palatable for humans, farmed flies are typically processed into products like protein powder or flour. Methods include controlled rearing, and heat treatments like drying and cooking to eliminate pathogens.