Sugar: Sweet Poison

It is natural for us to love sugar, so instead of feeling guilty as you reach for your third biscuit, take a few moments to understand why you may be doing it. Humans are designed to eat carbohydrate as a fuel and to be attracted to those foods which contain it. Naturally sweet foods are also more likely to be safe to eat and this is possibly a mechanism by which we historically protected ourselves from poisoning.

However, when our ancestors ate sweet things, they were mostly packaged within foods that also contained many nutrients, enzymes and fibre that both nourished us and helped the food to be absorbed and used by the body. The sweetest of these foods, such as berries and honey were not available all year round or were hard to get hold of. If you managed to locate a tree containing a colony of bees, climbed it and succeeded in taking some honey under the watchful guard of its flying sentries, you were doing well. However, you might pay in stings and grazes and you were certainly unlikely to be doing it each morning as preparation for breakfast.

However, dipping our spoon into a jar of honey, a pot of jam or the sugar bowl, is something we can certainly manage, with ease, each morning. Now that we have learnt how to extract the sweet part of food, we have a virtually unlimited supply of it available to us and little to control how much we consume. It is there in every season and we don't have to eat a barrowful of apples or carrots to get it. Isolated from the whole food, it is digested quickly and, with nothing to slow its release into the bloodstream, our blood sugar rises faster. Too much sugar in the bloodstream is dangerous for our bodies but an ancient system keeps it from harming us. The hormone, insulin, removes excess sugar and packs it away for later use, either in the liver (the kitchen cupboard, where we can get at it quickly) or as fat (in the cellar). This is a great system. In the autumn, our diet richer in sweet fruits would allow us to lay down stores of fat to get through the winter and to protect our blood vessels from leaking, when vitamin C rich foods were in limited supply.

However, our bodies have not adapted to this significantly higher and more regular intake, especially when combined with a lower level of exercise. Under these pressures, the system may start to work less well, potentially leading to chronically high blood sugar levels and corresponding damage to body tissues, which has been linked to a number of chronic health issues, including diabetes, cardiovascular damage and cognitive decline.

So as you reach for that fizzy drink, third glass of orange juice, slice of cake or bowl of white pasta, try giving some thought to which is more costly for your body: climbing the tree or reaching for the spoon.