Sustainable Protein Sources

Cows are expensive.

Cow meat, in particular, is resource-intensive.

That’s what worries people who look at population growth trends. Meat needs a lot of resources to grow, specially cows and such. And global demand for beef will continue to increase as people climb out of poverty and seek more efficient sources of nutrition.

Someone on Quora asked about the cost of growing crickets compared to the cost of growing cows for beef, and this particular answer had some numbers.

Alex Drysdale, CEO of Changing What We Eat writes the following:

Crickets are approximate 20x more efficient overall as a food source compared to beef.

They grow 13 x faster (6wks vs 18m) than cattle, 
on 2000 x less land (0.0125 acres vs 25 acres),
with 2000 x less water and 13 x less feed. 

I wanted to find the equivalent amounts of each animal to produce the same protein, so I calculated a few things.

How many crickets would it take to grow a cow’s beef worth of protein?

Disclaimer: I have not added sources to this, I just did quick Google searches for numbers that seemed reasonable and rounded extremely variable ones. I might add better sources in the future.

How much protein does an average cow have?

Let’s take a big cow that reaches an adult weight of 680 kilos.

43% of the cow’s weight is meat for consumers. That is 292.4 kgs of beef.

1 kilogram of beef has an average of 154 grams of protein. (depending on the cut)

292.4 kgs of beef therefore contains 45 kilograms of protein.
This is, roughly, an estimate of what an average cow that weight would have.

How many crickets does one need to produce 45 kgs (1 cow’s worth) of protein?

1 kilogram of crickets contains about 129 grams of protein.

Dividing that by 2.86, we know that there are 45 grams of protein in 349.6 grams of crickets.

45        - 349 600
  4.5     -   34 960
  0.45   -     3 496
  0.045 -        349.6

Multiplying (4.5 x 10^-2) and 10^3, we get 45 kilos, and the corresponding amount of crickets needed to produce that is 349 kilos. That is a third of a tonne!

If an average 6-week old cricket (adult) weighs give or take 385 grams, it means that we need about 910 crickets to match the protein content of a cow’s worth of beef.

How much water is needed to grow that cow versus all the crickets?

A cow, on a normal day might need about 26.5 litres of water, depending on temperature. On hot days it might need twice as much!

Over 77 weeks, which is the 18 months a cow takes to grow full-sized, this consumption amounts to 14 283.5 litres of water.

A cricket consumes about 2000 times less water than a cow, according to Drysdale above. This is about 0.0135 litres daily, or 13.5 mililitres (grams).

910 crickets, drinking 13.5 grams of dat H20 stuff amounts to 12 litres a day.

Over the course of 6 weeks, the time it takes for them to grow from pinheads to adult-sized crickets, this adds to 504 litres.

If we take Drysdale’s figure of a two-thousandth the water intake of a cow, but adjust for equivalent protein output, the more accurate number is a 1/28 the water input.

Let that sink in.

This means that in 7% it takes to raise a cow, and with 3.5% of the water used.

Our dependence on meats from vertebrates is a heavy burden on ecosystems and takes up a lot of energy, which drives currently a lot of emissions into the atmosphere. It contributes to droughts (I am looking at you, California), and it means land is cleared.

It also serves as a distraction. Who gives two monkeys’ if the beef is organic? Or freerange? Those points are on very shaky ground here. Seriously.