The simplest reason why we think a calorie is a calorie

I was recently involved in a friend’s Facebook discussion that involved nutrition. In fact, it was ignited because my friend had linked through to this article:

I’m not going to talk about that article specifically here, but, about a comment left on the comment trail that: “At the end of the day [this nutritional stuff] is fiddling around the edges, it is a mathematical issue. Calories in/calories out.”

I won’t embarrass my friend, or the commenter but I think it’s worth addressing that comment more fully.

The simple explanation as to why people think calories in/calories out is all there is to weight gain.

This is the explanation in all its simplicity:

In order to move, breathe, think, digest etc we need energy. Food contains energy. If we take in more energy than we expend then that energy is stored as fat – and we gain weight.

In other words, it is assumed that our bodies are self-contained machines that require only energy from food to do everything it needs to do. This would be similar to a steam engine. It gets its energy from burning coal, which boils water, creates steam and moves the pistons. In other words, the only use the engine has for its fuel is energy. The machinations of the pistons are all internal to the engine – they require energy to move, but for nothing else.

steamengine_1038In our analogy – and if the above explanation is correct – that would mean that similar to the steam engine – all of our internal machinations: our lungs, heart, brain, bones, muscles, endocrine, immune and many myriad other organs, functions and systems are all totally self-contained. They only need energy to work. They only need energy to grow. They only need energy to rebuild.

In the imagination, that seems conceivable. Our bodies are incredibly sophisticated biochemical machines. Its genes can code for the building of countless proteins by specifying sequences of amino acids (built from the most raw of raw (internal) material). And these proteins, and other similar molecules, are therefore synthesised internally – the only thing the system requires from the outside energy.

Except that’s not the case.

Life, the universe, and everything in it is a series of chemical reactions.  We suffer from an arbitrary sense of coherence that makes the assumption that somehow we are absolved or different from this constant transaction. We aren’t. And we don’t. In order for our bodies to exist it needs to constantly transact with the molecules in the environment to build and repair itself.  It needs the molecules themselves not just the energy contained in their atomic bonds to build and repair.

That is what people mean when they talk about ‘essential’ amino acids, or vitamins or or all manner of other things. Food is not just energy, it is not just calories. It is a cocktail of molecules that the body uses to help build and maintain its pistons.

How do we know? Here’s a very simple example: if you are deficient in an ‘essential’ nutrient you can suffer from crippling diseases – just think of Rickets and Vitamin D.

So what does that mean?

Lets say you have 100 cals of food A that contains a mono-ingredient for which your body as little use other than to break it down for energy. Let’s call that a small block of white sugar.

Lets say you have another 100 cals of food B that contains multiple ingredients for which your body has lots of uses. Lets call that kale.

The body will have no choice but to convert that sugar into ATP – the currency of energy in the body. And, if there is a surplus of energy (more than the body needs) the energy will be stored – as fat.  On the other hand, I wonder how much of the kale will even be left to be converted into ATP after its molecules have been feasted upon to access the 10s of vitamins and other micronutrients it offers?

So it’s more than just maths. Much more.


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