The past couple of posts have been looking at the problems with nutritional science in general, and issues with the paleo diet concept in particular.

I think that it’s important when it comes to nutrition (or any aspect of life) to keep an open mind, and question your beliefs.

I suppose the question is now – If so much of nutritional science is suspect, and the paleo diet concept itself is somewhat flawed, how on earth do we make a decision as to what and how to eat?

In this post, I aim to begin to set out some guidelines, as to how to make your own personal decisions about what to eat, and what not to eat.

The point of this post is not to lay out a one size fits all diet plan, as I do not believe there is such a thing. It’s purpose it to tie together what science does actually know about nutrition, and put that into a framework in which you can make an assessment about which foods you choose to eat, why you eat them, and how and when you do so.

What is food?

An ongoing argument within the nutrition world is whether there are such things as good and bad foods? It’s a question I get asked all the time. The conventional wisdom is that there is no such thing – any food can form part of a “balanced diet” (I’m picturing a see-saw with fresh meat and veg on one side, and doughnuts and pringles on the other). The opposite extreme would have you eschew tomatoes and aubergine as they are evil new world nightshades that will compromise your heath.

I want to turn that argument on its head by putting forward the notion that in fact;

There is no such thing as food!

Bear with me a second – I’ve not gone completely mad and started advocating a breatharian diet or anything! (Although it is very low in omega 6)

Human beings, like all other living organisms on this planet, survive, grow and reproduce by taking other living (or at least recently living) organisms, breaking them down into tiny pieces, and assimilating them into their own being.

Grass gets eaten by a cow, and with the help of the bacteria in its stomachs, the cow breaks the grass down into tiny molecules, absorbs them, and puts them back together as a cow. The cow then gets eaten by a human, and with the help of the bacteria in our guts, the cow gets broken down into tiny molecules, and reassembled as a human. Eventually we die, get buried in the ground, where, with the help of some more bacteria we are broken down into tiny molecules, before being taken up by the roots of some grass, and turned into fresh green pasture, and so the amazing cycle continues.

This is the process of life on our planet, and it’s truly remarkable. (There are those, i.e. Vegans, that believe that this process is now optional. That we no longer have to consume organisms that look vaguely like us because they’re special, and that plants don’t require the life of a dead animal to grow, but that’s for another post)

What is important to realise however, is that this incredibly complex and intricate web of endlessly recycled and reconstituted life on our planet is not the end result of a carefully designed and executed plan, but the end product of millions of years of trial and error.

I have written before that it is a mistake to think that any food either does or does not want to be eaten. It is only humans that have wishes and desires. Equally, no living organisms were designed for any purpose, let alone to be eaten by humans, or any other species.

The label food is applied to living organisms which we choose to eat. The only thing that connects the organisms that we label food to each other, or separates them from those that we don’t, is the fact that we choose to eat them.

Let’s think about a few different organisms, some which we label as foods, others that we don’t:

Cow, Dog, Edible Frog, Poison Arrow Frog, Button Mushroom, Fly Agarick Mushroom, Broccoli, Ornamental Cabbage, Grass, Wheat.


The first four organisms are all animals, two mammals and two amphibians. Chances are if you are reading this blog in your first language, you only consider the first one on the list (cow) food. In other parts of the world dogs and frogs are popular items on the menu, however no-one would consider a poison arrow frog food – Or at least not for long, as eating it would kill you pretty much instantly!* We then have two fungi and four plants, half of which are edible, the other half not, either because they’re highly poisonous, or just too hard to digest.

*[NB – In the paleo world people often talk of plants containing toxins as defence against predators as they can’t run away. It should of course be noted that there are plenty of highly poisonous animals out there too which you’d be strongly advised to avoid sticking on the barbecue…]

In short, we label the cow, button mushroom, broccoli and wheat as food, for no other reason than that we choose to eat them. Apart from being living organisms, the fact that we consider them as food is the only thing that connects each of these items – biologically they are each much more closely related to other the organisms that we do not consider as food.

Who gives an organism the label food and why?

Looking at the above list, it is quite obvious why some of the organisms are not categorised as food – they are either highly poisonous, or totally indigestible.

How about the other items though? Who decided which should be classed as food, which shouldn’t, and why?

Let’s go back to the question, “What is food?”

We’ve established that food is essentially other living organisms, that we choose to devour in order to live, grow and reproduce.

All living organisms are a potential source of the following four factors:

  • Energy
  • Raw Materials
  • Toxins and Anti-Nutrients
  • Pleasure


Energy is the essential component of life – It is vital for every bodily process – For growth, movement, regeneration, brain function, everything. Plants can convert the energy of the sun into carbohydrate. We must get our energy from either eating plants, or eating other organisms that are further up the food chain.

Raw Materials

You are what you eat, literally. The other organisms we consume are dismantled and then reassembled as us. The body is very ingenious – it can manufacture a wide range of proteins, fats and carbohydrates from many different sources. Certain raw materials however, must be supplied by the diet, as the body cannot manufacture them itself. These raw materials include, but are not limited to: Essential Amino Acids, Essential Fatty Acids, and Essential Vitamins and Minerals.

Toxins and Anti-Nutrients

Living organisms can contain elements that are toxic to us when ingested, or which bind to the nutrients inside and prevent them from being digested. While these were not purposefully put there by some designer as a form of defence mechanism, the fact that their occurrence might make eating the organism less appealing to predators may well give it an evolutionary advantage.


Food can be a source of pleasure. Looking at things in the light of evolutionary biology, it would seem to make sense that organisms that have a taste for foods which are high in the nutrients that they need, and low in toxins and anti-nutrients should have an advantage over those that love to eat foods which don’t. Perhaps this is an over simplistic view however, that doesn’t necessarily hold up to scrutiny.

All living organisms can be assessed on each of the four categories above. In general, one would expect that for an organism to have been classed as food it should contain sufficient energy and nutrients to make it worthwhile sourcing, be relatively low in toxins and anti-nutrients so that it posed no risk to health or well-being, and if not a source of pleasure, at least relatively palatable.

In the animal kingdom, where foods are eaten purely on instinct this is often pretty much the case. Human beings on the other hand are far more complex, and as always, things are not so simple!

Over the next few posts, I’m going to look at the above four categories in detail, and how their relative importance can be widely different for each individual depending upon their goals, genetics, health and tastes, and how they can be used in order to delineate your own boundaries for what you class as food, and what you do not.

Thanks for reading, I hope you found this post of interest. I would love to hear your thoughts and comments below, or feel free to tweet me at @Simon_Whyatt

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