In the 2018 book The End of Animal Farming, author Jacy Reese Anthis interviews Alex Lorestani, co-founder of Geltor, a company that produces food- and cosmetic-grade gelatin without animals. Geltor uses microbial fermentation: genes for gelatin are introduced into microbes — think baker’s yeast. In highly controlled bioreactor vats, the microbes can decode the DNA to produce gelatin, thereby eliminating the need for cows and pigs to do the same. Alex, just a few years removed from completing his doctorate in molecular biology at Princeton University, explains his motivation to Jacy for starting Geltor. He wasn’t moved by the ethics or environmental concerns; instead, he seethed with “technical outrage.” Alex quipped to Jacy that using animals is “the dumbest way to make the things that we need and love.”

Over the years, as the alternative protein industry burgeoned, we’ve heard a lot about how inefficient animals are at producing goods, and the need to switch. Liz Specht, vice president of science and technology at the Good Food Institute, presented striking numbers to a San Francisco audience in February 2020: only 11% of what’s fed to chickens is converted into human food, and cows convert a paltry 3-4%. Liz expressed similar frustration over the efficiency of animals, and explained how this contributed to her going vegetarian in college.

In this post, I’ll delve into the details of just what makes animals so pathetic as bioreactors — machines to produce commodities such as meat, dairy, clothing, and biologics — and how those metrics lead to environmental and ethical calamity. As the presentation continued, Liz explained some of the reasons for the inefficiencies of animals: they walk around, have circulatory systems, and “waste” much of what they eat on their activities, specifically what systems/quantitative biologists such as myself term as “maintenance.”

Biomass And Maintenance

Illustration by Julia Allum and Karthik Sekar

In contrast to maintenance, the other endpoint in the animal bioreactor is biomass. Biomass is the physical aspect of the animals: the bones, muscle, milk, blood, and anything else that is physically tangible. In other words, biomass is tantamount to all of the commodities that animal agriculture reaps, including meat, dairy, clothing, drugs, and cosmetics. In order to squeeze the most out of animal bodies, producers would love more of what they feed to build biomass rather than to be burned by maintenance.

Data from (West et al). Illustration by Julia Allum and Karthik Sekar.

An influential quantitative biologist team of Geoffrey West, Brian Enquist, and James Brown (the WEB team) figured out that the allocation of biomass and maintenance quantitatively predict how animals grow over time including cows, hens, and pigs. As many of us are familiar, especially with companion species, young animals’ growth is explosive: they grow quickly in their first weeks and months only to slow down as they reach sexual maturity. Animals put on less mass as they grow because their maintenance requirements are proportional to body size. When they’re young, they are small, and more of what they eat can fuel biomass. But the maintenance tax penalties only go up and eventually the cost is one to one: everything the animal eats pays purely for maintenance. 

Using the WEB team’s framework, I calculated the lifetime fraction of biomass versus maintenance at a paltry 14%. That means animal agriculture producers lose, at least, 86% of what they feed animals to maintenance. In contrast, microbes such as the ones driving Geltor’s gelatin process can have a much more impressive yield, sometimes reaching over 99.5% in the right bioreactor conditions, because microbes do not grow in the same way as animals. So in the long run, processes such as what Geltor is doing will technologically surpass the cow bioreactor, at least in terms of yield.

Too Generalist And Too Big

The bloated maintenance cost for animals can be explained by two reasons: 

1. Animals are complex generalists that evolutionarily developed to survive in diverse environments on many types of food.
2. Animals are so big that they need intricate, costly circulatory systems

Consider all the types of biological life: conifer trees, sea slugs, the firmicute bacteria in our gut, the fly agaric mushroom, and animals. Compared to other domains of life, animals tend to lie on the more generalist and complex end: They are mobile, they can inhabit many kinds of environments, and they can eat many kinds of food thanks to their stomachs which help acidify slurries of food into metabolizable molecules. Furthermore, animals are capable of complex assessments: a predator or prey looms behind the trees, this fellow is a friend, or this place is safe to sleep tonight. 

The more functions a species has, then the more resources, i.e. maintenance is required internally by the organism. The brain and the accompanying sense of smell, taste, sight, and feel will demand more energy to run the necessary calculations. Muscles are required to propel the animal forward or up — sometimes quickly if a predator looms. A sophisticated gastrointestinal system is needed to excavate nutrients from meat and different kinds of plants. It’s a “jack of all trades, master of none” scenario, and each aspect depletes the efficiency to create biomass.

In contrast, microbes are specialists. They generally can only consume a few types of molecules such as simple sugars, amino acids, and peptides, and they can mainly sense those molecules and nothing else. They must inhabit the perfect environment: enough moisture with the perfect pH, temperature, and salinity — all of which is controllable in a bioreactor vat. Otherwise, the microbes die or lose out to more adapted competitors. The tradeoff is that they don’t have the baggage of brains, stomachs, or muscles and, accordingly, require less maintenance. 

Animals are also big with respect to most biological life. Their size demands a sophisticated circulatory system to move nutrients, hormones, and waste to and from entry and exit points. Organs such as the heart and lungs vitalize the entire body. Circulatory systems are so costly, that the WEB team found that the fractal patterning of blood vessels is Evolution’s way to curb the cost. The branching minimizes the friction of moving blood through the body. 

Microbes are smaller, microscopic to be exact. In this world, nutrients and waste can pass via chemical diffusion. An oxygen molecule can bounce from one end of a microbe to the other in 2-3 microseconds. Stated another way, the oxygen molecule can bounce end to end nearly half a million times within just one second. They do not require any semblance of a circulatory system. And in a bioreactor vat, this is perfectly fine because a spinning impeller can bathe microbes with circulating nutrients.

Animals Grow Slowly Too

Circulatory systems also cap the speed at which animals grow. It’s energetically costly to speed up fluid flow. If a heart works twice as hard, i.e. uses twice the energy, then the blood flow only ramps up 1.4 times. Returns diminish very quickly. It takes at least months, if not years, for animals to become full size. In contrast, a microbial bioreactor vat process could take mere hours.

This bears out in the numbers: microbes can grow 1,000-10,000 times faster than chickens and cows. To put this in perspective, if we had a celestial-sized bioreactor vat, and we seeded it with one baker’s yeast — a quarter the size of a red blood cell — and ran the reaction, then we’d have yeast biomass equivalent to Earth’s mass in just eight days.

Consequences to the Terribleness of Animal Technology

The technical inferiority of animal-based production also explains awful environmental and ethical outcomes. Animal agriculture is responsible for 5% of carbon dioxide emissions globally. This doesn’t seem so bad based on the analysis above. However, this 5% undersells the biggest environmental problem of animal agriculture: its extensive land usage. Nearly 30% of ice-free land on the Earth is used for animal agriculture. That’s a lot of land to not have trees on. In other words, animal agriculture incurs a massive environmental opportunity cost. Because humanity spends so much land on animal agriculture, we’re less able to sequester carbon dioxide with forests or trees. This is explained by the metrics of animal technology. If one has an irretrievably slow process, then just make the process bigger. If we could instead use the more efficient microbial fermentation vats to replace cows, then we’d free up 99.9% of the land. 

In terms of ethics, producers have learned that they can ameliorate the awful metrics of animal technology. Specifically, animals in confinement grow faster than they do in free-range settings. The yield is better too; they’re not wasting the precious feed on frivolities such as walking around or playing with friends. Concentrated animal feeding operations (CAFO), or factory farms, have thrived because of the terrible metrics of animals. Free-range animal husbandry just doesn’t scale. Accordingly, CAFOs supply 99% of the animals in the United States for meat.

Hope and Opportunity

Since the Enlightenment, humanity has developed a penchant for replacing outdated, plodding technology with better, more helpful technology: Candles to light bulbs. Abacuses to a computer. Oxen to tractors. Horses to cars, motorcycles, and trains. 

Likewise, it’s inevitable and imminent that we’ll replace animal agriculture for technological reasons alone. I’ve written After Meat to convince the world of that fact and, importantly, to get excited about it. It will be better in every meaningful way and not just for the environmental and ethical outcomes. Because animals are limited machines, the gastronomical possibilities are, likewise, fenced in. We can have food that tastes better, is healthier, and cheaper than anything that was possible using animals. We could solve world hunger much easier with more efficient technology. This future might happen via microbial bioreactor technology, as I’ve extolled throughout this post, but there are other viable alternatives too.

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100% of the profits of After Meat will be donated to charities, including Faunalytics, to help circulate and provide the key knowledge that catalyzes the world toward newfound amazingness without animal products. After Meat will be released on November 16, 2021. For news and further information, check out aftermeatbook.com.