The secret life of sugar- how evolution makes us wired to like sweet things for survival

Laurentia (Laura)Campbell
5 min readJan 23, 2022

Fruit, meat, dairy and vegetables contain lots of essential carbohydrates vitamins, minerals, unsaturated fats and antioxidants like vitamin C, K, D, iron, B vitamins like Folate and Thiamine, calcium, omega-3, selenium and many more. Human brains are no different to our prehistoric cavemen ancestors (brains take millions of years to evolve), and so our behaviour is still dictated by our desire to survive, thrive and continue the human species. Humans need the essential vitamins and minerals in fruit and veg to survive.

We need sugar to survive

Fruit and vegetables also contain lots of natural sugars like Sucrose and Fructose. We need this sugar for energy to survive. Cavemen needed it for energy to go out and hunt, reproduce and escape predators. Every cell in our body needs some energy. So our brains evolved to increase Dopamine brain chemical (neurotransmitter), the pleasure neurotransmitter in our brain when we consume sugar. This makes us feel pleasure and, as Dopamine works in conjunction with Serotonin happiness chemical, improves our mood. So our brains evolved to like fruit and vegetables. They were sweet, so made us happy and so we ate them and consumed the essential energy, vitamins and minerals we needed to survive, have fertile offspring and continue the human race.

Redefining sugar with refined sugars

Over time, humans have refined and refined sugars and even turned them into new chemicals we call “sweeteners”. These new sugars are far sweeter than sugar (some sweeteners are up to 1000x sweeter than sugar). They cause a massive surge in Dopamine in our brains, which makes us hugely enjoy these products, and so we buy and consume more and more of them. The manufacturers of sweet things know this and so they refine the sugars more and more to make us buy more and more of their products. They even fooled us into thinking these sugars were “healthy” by calling their products with these sweeteners “sugar-free” and telling us they would help us lose weight.

However, these products have in fact dulled our sensitivity to sweet things. When we consume something 1000x times sweeter than fruit, dairy and veg sugars and get the huge Dopamine buzz, and then consume simple and complex unprocessed sugars in dairy and plant-based foods, our brains just cannot get the same Dopamine high, and so we find fruit and vegetables boring and flavourless. We can actually change our taste buds and gut-microbiota, making it even harder to enjoy basic sugars. Just like all things that cause a Dopamine buzz (alcohol, cigarettes, fat, sex, our phones, achieving things), once we have pleasure, we often want it again, and then again and develop a tolerance to the same high, become addicted to it and need more and more of it to get the same level of pleasure we once received. We get addicted to it. It increases our desire, our appetite for sweet things. Humans are not addicted to sugar (this is a common misconception), we are addicted to man-made, highly refined and processed sugars and this is a huge part of the obesity epidemic, especially in the USA where processed sugars coat most things. As the sugars also increase the shelf life of products and make them more appetising, even most nuts and fruit and veg are now coated in these modern sugars. They flavour waters, tubes of toothpaste, mouthwashes, are in heartburn tablets and children’s vitamin chewable tablets. It is hard to escape them.

It’s all about the sell

Manufacturers of highly processed foods are very aware of the negative scientific research emerging on this topic. Like cigarette companies in the 1960’s when science research discovered the link between cigarettes and heart disease, they know it but they want to keep you addicted so you keep buying their products. They know their products cause obesity, diabetes and heart disease. They know their foods are addictive but they want you to get addicted, as cigarette companies did/do, so you buy their products and they make lots of money. To get around this, they don’t name their sugars with E-number additive or chemical-sounding names, they make them sound natural by calling them things like “Sucralose” or “Saccharin” which both sound and read like the natural sugar sucrose or “Maltodextrin” which sounds like the natural sugar Maltose. They make use of the fact most people are not scientists and do not know the specific chemical names for sugars and they market their products as “sugar-free” so you buy them. You are still getting sugar, just a new kind of sugar that is actually more likely to make you fat, as it increases your appetite for sweet things. They are clever with branding to say “fat-free” and “sugar-free” so you feel you are being healthy but don't be conned by it, it is actually the opposite.

Sugars are not bad. They are delicious. Natural plant or animal-based sugars from Glucose to lactose (the sugar in milk and cream), honey to beet sugar to coconut sugar to agave nectar, are often in things that contain the vitamins and minerals we need to survive, feel happy and live long and healthy lives. They make us happy and everyone deserves a sweet treat now and then. Where it all goes wrong, is when we consume too much sugar and processed sugars. This is what makes us fat, unhappy and unwell. This is what we need to change. We need to Dopamine detox the western diet.

So how do you recognise what's and not?

Common examples of names for natural sugars

  1. Glucose
  2. Fructose
  3. Galactose
  4. Lactose
  5. Sucrose
  6. Amylose
  7. Coconut sugar
  8. Honey
  9. Agave Nectar
  10. Chicory

Common examples of names for refined sugars

  1. Maltodextrin
  2. Corn Syrup
  3. Dextrose
  4. Saccharin
  5. Aspartame
  6. Acesulfame K

And many many more.

Be careful. Even “roasted and salted” Cashew nuts in Ikea come coated in sugar (it increases shelf life).

Disguised sugars on Ikea salted nuts- source Laura Campbell/ Ikea
Disguised sugars on Ikea salted nuts- source Laura Campbell/ Ikea

Copyright Laura Campbell 22/01/2022

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Laurentia (Laura)Campbell

Neuroscience, mental health and nutrition academic and writer. Life-experimenter, trying to add value with an insatiable appetite for actioning positive change.