It’s easy to undermine the green energy transition with one simple question: why do we cook food?

Before I get a bunch of inappropriate emails in the feedback inbox, let me ask that same question in a different way: why did we start cooking food?

However uncomfortable your experience of uncooked food might’ve been more recently, we didn’t always need to cook our meals.

So, why did humans suddenly bother to go through the long and laborious process of gathering firewood, starting a fire, preparing the food to be cooked, waiting for it to be cooked and then waiting for it to get cold again?

It must’ve been hard to persuade people to bother putting up with all this nonsense when it was first tried. Can you imagine Jamie Oliver’s ancestor trying to convince his tribe to “burn” their perfectly good, raw meat 780,000 years ago?

So, why did we suddenly bother to turn on the stove? Is the answer something to do with taste?

Perhaps, but the popularity of steak tartare, sushi niku (raw steak), dancing octopus (it’s still alive), raw chicken heart and sushi suggests there’s more to the story.

Was cooking about the health benefits? That was probably part of the story, especially given the safety issue we are now so sensitive to.

But a group of researchers and historians have come up with an alternative theory. One which would blow today’s green energy transition out of the unboiled water… or result in us eating a lot more raw food in the coming decades…

The story goes a little something like this: we cook food because it is more energy efficient.

There’s no doubt that that sounds a bit ridiculous. The amount of energy it takes to cook a meal today can feel draining. Imagine having to gather wood and make the utensils yourself, too.

But there is a very long list of ways in which cooking food actually makes the overall process of feeding yourself more energy efficient. And it’s not just because gathering firewood gives the kids something to do elsewhere, while you prepare the meal in peace and quiet.

Perhaps, I should first point out that food is, of course, energy itself. It’s human fuel. So, what we’re talking about here is an energy system from start to finish, not just the pleasure of eating a steak.

So, why gather fuel and apply energy in the form of fire just to make steak medium rare?

A good chunk of the answer lies in chewing and digestion. Apparently, it takes a lot of energy to digest food. But it takes a lot less energy to digest cooked food.

Food historian Rachel Laudan explained the trade-off on the podcast EconTalk:

Animals, if you think of the standard picture of a cow, they first of all spend a lot of time wandering around, chewing grass, which is tough. And then they have stomachs and they spend much of the day digesting this food.

It takes a huge amount of energy to digest food. So that when you cook, what you are essentially doing is outsourcing digesting — chewing and digesting — into the kitchen. And doing it previously. And that saves a lot of energy for the humans who are lucky enough to eat the cooked food.

Of course, the energy has to come from somewhere, and part of it is from the thermal energy of the fire; but part of it is from the energy of the people or animals or later on wind or water or steam that are doing the hard work of grinding.

So, cooking is about outsourcing part of the energy demand of fuelling yourself. And it is a more efficient overall system. Especially when someone else is doing the cooking for you…

Cooking also unlocked other forms of food we couldn’t previously use, a bit like oil refining and gas liquification today.

Can you imagine what society first thought about the idiot who decided that grains would make a good food source?

I mean, the amount of energy expended in turning grain into food 20,000 years ago would’ve been quite an effort.

First, you have to turn grains into flour, which is surprisingly difficult. Laudan explains the details again:

It was brought home to me when my father, who was a farmer and who grew hundreds of acres of wheat decided it would be interesting to make bread out of his own wheat. And in those days, you couldn’t just google and find out how to do it. So, he set about taking these grains of wheat; and he beat them in a pestle and mortar, and he ground them through a meat grinder, and he hit them on the stone floor of the kitchen. And all he got was squashed grains.

You have to use a shearing action — I learned that many years later when I moved to Mexico, where people still grind grains. And you have to use a lot of weight with both a vertical and a horizontal force to break up the outside husk and get into the flour in the middle. And that’s after you’ve cleaned them, and washed them, and threshed them, and done all the preliminary processes. That’s just to turn them into flour.

Despite the ridiculous amount of energy that it takes to turn grains into a useful form of food/energy, it turns out grain is an incredibly energy efficient form of food in particular ways, as Laudan goes on to explain:

Let’s go back to the Palaeolithic. Human beings, it’s pretty clear, were incredible careful and intelligent about inventorying the world’s food sources. They knew what was edible and what was not. They experimented and found out what was poisonous and what was not. And the trick was to find something that was nutritious, that was storable, that was transportable. And most foodstuffs just don’t live up to this.

Most foodstuffs are available only episodically, in the summer, in the harvest season, or, if they are big game, they are only available when you’ve got a big catch.

The really neat thing about grains is that they satisfy all those criteria. They are highly nutritious. They are highly storable because they are hard and dry, and they don’t rot and go bad. And they are highly transportable because they have a high food-value to weight ratio. Unlike, say, potatoes, which are very wet and heavy and therefore are hard to store and transport.

Grains, in other words, solved the energy problems which much of Europe is still struggling with today: winter and moving energy around to where it’s actually needed.

Laudan is, of course, not the only one thinking about all of this. Here’s a quote from the academic abstract of the paper, “The energetic significance of cooking,” by Rachel N Carmody and Richard W Wrangham:

In this paper, we evaluate the hypothesis that an important and consistent effect of cooking food is a rise in its net energy value. The pathways by which cooking influences net energy value differ for starch, protein, and lipid, and we therefore consider plant and animal foods separately.

Evidence of compromised physiological performance among individuals on raw diets supports the hypothesis that cooked diets tend to provide energy. Mechanisms contributing to energy being gained from cooking include increased digestibility of starch and protein, reduced costs of digestion for cooked versus raw meat, and reduced energetic costs of detoxification and defence against pathogens.

If cooking consistently improves the energetic value of foods through such mechanisms, its evolutionary impact depends partly on the relative energetic benefits of non-thermal processing methods used prior to cooking. We suggest that if non-thermal processing methods such as pounding were used by Lower Palaeolithic Homo, they likely provided an important increase in energy gain over unprocessed raw diets.

However, cooking has critical effects not easily achievable by non-thermal processing, including the relatively complete gelatinisation of starch, efficient denaturing of proteins, and killing of food borne pathogens. This means that however sophisticated the non-thermal processing methods were, cooking would have conferred incremental energetic benefits.

While much remains to be discovered, we conclude that the adoption of cooking would have led to an important rise in energy availability. For this reason, we predict that cooking had substantial evolutionary significance.

The lesson here is that life is about energy efficiency, in the broadest sense, which includes reliability, storage, cost and plenty more. The more efficient our energy system is, the more we can get out of less.

And the act of cooking may have been our first energy transition – a global revolutionary improvement in how we manage our energy systems on which we depend for survival. It certainly puts The Great British Bake Off into perspective.

Here’s the connection to the green energy transition today: since coming up with cooking, we have never transitioned to a form of energy that is less efficient, more expensive and less reliable, ever. Not in the history of civilisations actually holding up, anyway.

Each transition in history, from solar to wood to windmills to coal to oil to nuclear was about getting more for less. It was obvious why we were conducting the energy transition, and so nobody had to force it upon us.

The historian I quoted above, Rachel Laudan, wrote a book that connects the emergence of empires with advances in cuisine. (You can find out more about the book here.) I can’t help wondering if there’s a causal link: whether empires achieved advantages by developing more efficient food systems or not.

I recall a story that the British Empire was built on the back of the army’s discovery that you should dig your latrines downriver and downhill from your soldiers’ water source. This revelation resulted in a far higher proportion of British soldiers being able to take to the field compared to their opponents, who were busy filling the latrines instead. But it may be a myth.

Today, we are being told that we must transition back down the ladder of energy performance. We must go back to wind and solar – the oldest forms of energy which we once relied on to grow our crops and mill them. These are less reliable, cannot be stored up and cost more once you take into account factors like the space they take up, the resources needed to build them and their useful lifetime.

As a result of this loss of energy efficiency, we must put up with less in order to achieve net zero – less travel, less meat, less money after paying our energy bill.

Once you understand the nature of energy transitions, you will begin to realise the implications for the economy as a whole. We will be unravelling everything that relies on cheap, abundant and powerful forms of energy.

At some point, for example, it becomes too energy inefficient to bother cooking food anymore. North Koreans can tell you all about this.

Or it becomes too inefficient to heat your home using electricity, as the Germans gathering firewood discovered last year.

If you upset the energy system, everything else goes with it. That’s why we’ve never been dumb enough to try this before… and lived to tell the tale.

It’s also why my friend James Allen expects a rather dramatic comeback for fossil fuels to save us from net zero.

Until next time,


Nick Hubble
Editor, Fortune & Freedom