why do humans crave sugar?

Everyone in the Western world is more than familiar with consuming sugar. It is in drinks, snacks and the food which makes up the majority of our meals. Recent...

Everyone in the Western world is more than familiar with consuming sugar. It is in drinks, snacks and the food which makes up the majority of our meals. Recent estimates show that the average American consumes 22 teaspoons of sugar a day, and in the UK we are not far behind. Yet since the 1670’s sugar has been associated with diabetes, and since then its relation to modern diseases has become more and more obvious, so why is consumption increasing? This article will explore the reasons why, despite all the risks, we crave sugar, and investigate just how unhealthy it can be.



The habitat which early man lived in is much different to the one we live in today, yet it is this early habitat which our body evolved to thrive in. There were no fridges, very basic or no farming, no pesticides, no artificial lights, no food processing, no clocks, no sweets, no money or super markets. There was actually almost no sugar in the diet which early man evolved to thrive off, they would typically eat animals, vegetables, roots and fruits. The only food which was abundant in sugar is honey, which was rare to find and difficult to get, so the only real source of sugar was fruits and to a lesser extent, vegetables. Early humans would crave these foods, not only because the sugars gave us an energy boost, but because they contained a vast array of vitamins and minerals. The sugars were in such a low quantity in these foods that they had no negative effect on our health, only positive, and our body evolved to recognize the fact that sugars are associated with energy and nutrients, resulting is a reward signal in our brains, which makes us happy.

This reward mechanism is still in place, which is why we love and crave sugar – it makes us happy. Refined sugars are a very recent development, something which has happened far quicker than it takes for evolution to compensate. This means that despite the fact that sugar now actually is the cause of a number fo diseases, our brain still recognizes consumption if sugar as a positive thing.



We have ascertained that our body is designed to crave sugar, but it is not only built into our biology, but it is built into our psychology. From a young age we are taught that crisps and chocolate are treats or a reward, something we get for good behaviour or achieving something. This association gives us a taught feeling of reward, which only serves to reinforce our evolved feeling of reward from sugar. As we grow out of childhood this associated of sugar and positive feeling is embedded in our mind, but as we become in charge of our lives, these rewards are not something which the parent controls, but something we control. Adults are able to stimulate this feeling of reward as much as they like, which can result in becoming over weight, which in turn, makes you unhappy causing you to crave more sugar. This is a typical cycle which many overweight people find themselves in.


Sugar – The father of modern diseases

In 1675 sugar was discovered to be associated with diabetes, in the 1920’s this was confirmed to be the cause, in the 1960 it had been demonstrated in a number of studies that sugar consumption caused an increased risk of heart disease, weight gain and diabetes, and in over the past 30 years it has been shown to increase the development of cancer. Heart disease, obesity, diabetes and cancer are the 4 main modern diseases which are claiming more and more lives each year, and sugar is know to cause all of them.

Diabetes (type 2) – Sugar causes us to produce large amounts of insulin, which signals cells in our muscles and liver to store sugar as energy (fat or glycogen). Regular sugar consumption causes our insulin levels to remain high, and so our cells become resistant to it, and stop storing energy efficiently, meaning blood sugar levels remain high. In response to this high level of blood sugar, our body produces even more insulin, which in turn results in higher resistance in our cells. This continues, and ultimately exhausts the insulin producing cells in our body, which damages them and they become unable to produce insulin effectively. This results in an inability for our body to regulate our blood sugar levels and increases our risk of a number diseases such as obesity, cardiovascular disease and a variety of health complications.

Obesity – Our body is designed not to waste energy, if we consume more energy than the body needs our body stores it in case we don’t get food later. Remember, the environment our body is designed for doesn’t have supermarkets or fridges, our body doesn’t know where our next meal will come from, and so prepares for the worst – starvation. As sugar is absorbed so easily by our digestive system, we have a flood of energy into our body which we rapidly store as fat. If we eat sugar regularly, then we store more and more fat. Complex carbohydrates, such as the ones that are found in vegetables are absorbed slowly which prevents a sudden influx of energy throughout our body, and so very little or no fat is created.

Heart disease – Heart disease goes hand in hand with obesity and diabetes, and if you are diabetic you are 48% more likely to suffer from heart disease. Diabetes often causes an unfavourable imbalance in HDL and LDL cholesterol levels, which will increase your risk of heart disease. Fatty deposits around blood vessels (which are known to be associated with obesity and caused by high sugar diets) restricts their movements, and reduces the diameter of arteries and veins. This causes an increase in blood pressure and a greatly increased risk of a rupture. These fatty deposits around arteries and veins can build up to dangerous levels before you start to look fat, and some people often look healthy when in reality, their veins and arteries are covered in fat. As it is often difficult to tell if these fatty deposits exist, many people are at risk without even knowing.

Cancer – High sugar diet is associated with cancer for a few reasons. Firstly, high sugar foods contain very little vitamins and minerals, which causes our immune system to become weakened. Our body creates cancer cells every day, but they are destroyed by our immune system before they can establish, but if large amounts of sugar are consumed, it is likely that you immune system is weakened and may not be able to destroy all cancer cells. Further more, just one teaspoon of sugar has been shown to inhibit the activity of immune cells for as long as 4 hours after consumption. This again provides a window of opportunity for cancer cells to develop.

Cancer cells are highly active cells, and require energy to thrive. We know that the consumption of sugar give our body an energy surge, which cancer cells will thrive on, and rapidly grow. There are a number of studies showing that low sugar diets reduce cancer growth and in some circumstances can almost stop it!



From our evolution and our childhood we have developed powerful reward mechanisms in our brain which are triggered when we consume sugar, which can result in illogical cravings for sugary foods. Regularly consuming sugar has been directly linked to the development of the 4 main modern diseases – cancer, diabetes, heart disease and obesity, all of which are rising in the Western world. Just by reducing sugar consumption can drastically reduce the risk of developing these diseases.




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Main image courtesy of Dhammza

I hope you enjoy the site, and like what we have worked hard to create, any feedback is very much welcome, after all this site is for you! Graduate of Nutrition & Food Science (Bsc) at Reading Uni.
  • bubbles

    Do you think there will be a point when we will evolve to dislike sugar? If you eat too many sweets you feel sick and get stomach aches, maybe if this sensation was brought on earlier?

    • Craig

      Probably not, evolution happens far too slowly, and the rules of natural selection are not applying to modern humans. We now tend to alter the environment too suit us, rather than adapting to the environment.

The Health Cloud was created in December 2011 by Craig and Morg who have been friends since high school. Our focus is to educate our readers with unbiased health articles and on the side we run our own online health shop. This website is for you, so drop us a comment or send us a tweet, we always take the time to reply!