Nope, I’m not talking about snow! This post is all about sugar. It’s that time of year when we become aware of how much we may have overindulged over the festive period. It’s quite a challenge to avoid the lure of sugar over Christmas, it seems to be on offer everywhere you turn. But what’s done is done, we can only change the future and not the past so no point in dwelling on it. I don’t believe diets and short term changes in diets are the way to go but some of us are making New Year’s resolutions and pacts with ourselves to change things and so what better time to think about what we are putting in. I hope this post helps you understand a little more about sugar and what it does to us.
Where does it come from
Most of the added sugar in processed foods is sucrose, a bit more on what this actually is in a bit. It’s made from sugar cane or sugar beet. These crops are farmed for sugar production on a huge scale around the world. The harvest goes through a series of processes to extract and refine what we know as sugar. It is an intensely concentrated product and something we have not always had in our diets in such large amounts. Whether the end product is brown sugar or white, it still goes through the same process, brown just has some of the molasses still intact and slightly less processing at the end.
Fruit is a great source of vitamins and minerals and other beneficial components but is still a natural source of sugars and should be moderately consumed. Some fruits are much higher in certain types of sugars than others and dried fruit is much more concentrated and easier to over consume. See below for fruit sugar amounts.
Different types
Sugar is a naturally occurring substance in wholefoods which is extracted, concentrated and refined and then added to processed foods as ‘added sugar’ to make them sweeter, add texture and structure and add shelf life. If you look at the nutritional information on the label of packaged food, the carbohydrates will be the naturally occurring complex sugars in a food, the ‘of which sugars’ or ‘sugars’ will be additional added sugars and simple sugars.
There are a few different forms simple sugars can come in – glucose, fructose and galactose which are single molecules known as monosaccharides Then maltose, lactose and sucrose which are two monosaccharide molecules joined together and are known as disaccharides. All are known as simple sugars. All can appear naturally in foods such as fruit, vegetables and milk but can have quite different effects once consumed and even more so when they are extracted from the wholefood source, concentrated and refined.
Glucose is the body’s energy source but it does not necessarily have to be consumed in this form, we can break down any carbohydrate into glucose inside the digestive system. Milk for example contains lactose which, when broken down in digestion is glucose and galactose. Table sugar, also known as sucrose is one molecule of glucose and one fructose. And foods containing maltose such as sweet potato break down into just glucose (maltose is just two glucose molecules attached).
So we need glucose but consuming foods containing glucose is not the only way we can access glucose if we need it for energy. We have stores we can call open in the form of glycogen, more on this in a minute, and we can produce glucose from lactate and amino acids which are derived from proteins.
Galactose is used in the body by the immune system and recent research suggests it is important for cells to communicate with each other. However, older research suggests consuming very high amounts of galactose has been linked to ovarian and prostate cancer. It is mainly found in dairy products but also in some fruits and vegetables in small amounts. With both these areas of research in mind, moderation is the key here.
Fructose is not required in the body and recent research suggests it is something to be avoided, especially in concentrated amounts, more on this in the next section.
What does it do inside our bodies?
Simply put, sugar is a carbohydrate and is used by the body for energy. When we eat carbohydrates, the digestive systems works away to break them down to the smallest forms – glucose, fructose and galactose. As I mentioned previously, there is a requirement for glucose and galactose within the body but not fructose. Glucose and galactose use the same mechanism of absorption into the blood, fructose has its own. Once in the blood stream each sugar has different consequences.
The body has feedback systems in place to make sure blood glucose remains as consistent as possible. An increase in glucose in the blood after a meal is followed by the release of the hormone insulin.
Insulins job is to get glucose out of the blood to regulate levels. It communicates with muscle cells to allow uptake of glucose for energy. In the liver it triggers packaging of glucose for later (glycogen) and it stops the other mechanism in the body from making glucose from its stores. All in an effort to reduce circulating blood glucose to an acceptable level. Insulin has other functions too with proteins and fat and stimulates fat cells to store energy. It is a measured system and the higher the blood glucose level, the more insulin produced. If Insulin is being produced constantly and at high levels, the cell receptors can become less and less responsive. This may lead to insulin resistance which contributes to metabolic syndrome. And eventually may contribute to factors effecting the development of Type 2 diabetes.
As I mentioned before, we don’t need to constantly consume glucose to make sure we have energy. The body can provide it via two other processes. If we have not recently consumed glucose then we can use the stores the liver made earlier – glycogen. Or it can make it out of amino acids and lactate.
If we feed our system with a constant supply of foods containing high amounts of glucose without using it up then we are unlikely to use what we have stored and our stores just keep building!
Large peaks in blood sugar triggered by large amounts of simple sugars consumed are usually followed by troughs of fatigue and so the craving cycle continues. These troughs are when you can feel tired, lethargic and reaching for more sugar for the next pick me up. It’s a much better aim to try and balance your blood sugar out so there are no huge peaks to deal with. Choosing foods which consist of as few simple sugars and more complex carbs as possible will help you on your way. Having protein with your carbohydrates can slow the release of sugar into the blood and incorporating healthy fats can keep you satiated.
Fructose is the sugar found mainly in table sugar, fruit and honey (see chart below) and is part of the disaccharide, sucrose (one fructose and one glucose molecule). Fructose is much sweeter than glucose and is often used in soft drinks and sweets as HFCS (high fructose corn syrup). It does not evoke an insulin response in the body and therefore has a low GI rating. So no insulin, no storage? Not quite! The body deals with fructose very differently. Once absorbed in digestion, it heads straight to the liver where it is preferably packaged as fat.
Research shows that high fructose consumption can increase the amount of fats circulating in the blood and increase the risk of cardiovascular disease. It’s been linked with obesity, raised LDL cholesterol and insulin resistance. There is also no feedback loop to suppress appetite when high fructose foods are eaten. And the more fructose you consume, the more you need to feel the same kick and so the addiction is born.
Did you know
Fruits and vegetables are grown sweeter now than ever before. Manufacturers are selecting sweeter varieties to appeal more to consumers. We are so accustomed to having sweet taste, even in savoury foods, when we don’t have it, we really notice. Jars of tomato sauce for instance can contain the same amount of sugar as a Mars bar!
Unfortunately the bitterness in vegetables is part of the most beneficial components. So we are effectively breeding the goodness out of fruits and vegetables. It takes time to become accustomed to less sugar in the diet, the more of it you eat, the less you actually taste it!
I hope this gives a better understanding of what happens when sugar is eaten and helps to give more reasons to try balancing your blood sugar levels.
The table below shows a few different foods and their sugar contents. We all know cakes and sweets contain large quantities of sugar, but some of the following may be surprising!
| Food (per 100g) | Total sugar | Total amount of fructose | Approx. tsp. of sugar |
| Avocado | 0.9 | 0.3 | 0.18 |
| Tomato | 2.8 | 1.4 | 0.56 |
| Milk | 5 | 0 | 1 |
| Pink grapefruit | 6.2 | 2.9 | 1.24 |
| Fresh FIgs | 6.9 | 3 | 1.38 |
| Nectarine | 8.5 | 3.1 | 1.7 |
| Fresh apricots | 9.3 | 3.3 | 1.86 |
| Banana | 15.6 | 6 | 3.12 |
| Grapes | 18.1 | 7.6 | 3.62 |
| Dried apricots | 38.9 | 15.4 | 7.78 |
| Dried Figs | 62.3 | 27.5 | 12.46 |
| Dates | 64.2 | 22.3 | 12.84 |
| M & Ms (chocolates) | 64.7 | 27.5 | 12.94 |
| Raisins | 65 | 33.8 | 13 |
| Honey | 81.9 | 43.2 | 16.38 |
| Brown Sugar | 89.7 | 42.1 | 17.94 |
| White sugar | 97 | 48.5 | 19.4 |
