Sugar is probably one of the most misunderstood substances often avoided by fans of healthy eating and exercise. Although sugar is often regarded as simply a sweet treat that should be consumed rarely and in small portions, many of the foods you eat daily and which are essential to your survival consist of sugar molecules. The best example of this is carbohydrates, one nutrient the body needs in large amounts, which consist of sugar molecules. The truth is sugar is very complex and this explains why it provides both nutritional advantages and disadvantages. In this week’s article find out why you shouldn’t be afraid of it!
From infancy we enjoy sweet taste; the first sugar we come across is lactose in breast milk. Sugars are pure, sweet-tasting carbohydrates that provide instant energy (20 calories per 5g teaspoon) and are an essential part of our eating habits. However, the sugars naturally present in foods are not a cause for concern; contrary to the sugar that is added to foods or drinks which increases calorie consumption and can lead to health problems such as obesity and tooth decay.
Types of Sugar
Carbohydrates are divided into three different groups: the simple sugars, the starches and fiber. Sugar is the basic building block of all these carbohydrates. But it gets a bit more complicated as the simple sugars include both the single sugars, known as monosaccharides, and the double sugars, known as disaccharides. The single sugars, glucose, galactose and fructose, contain only one type of sugar molecule. The double sugars contain two types of single sugars combined together. Starches and fiber are called polysaccharides because they contain three or more sugars.
Carbohydrates in the body
The main function of carbohydrates is to provide energy, but they also play an important role in the structure and function of cells, tissues and organs, as well as in the formation of carbohydrate structures on the surface of cells. The different molecular classes are the proteoglycans, the glycoproteins and the glycolipids.
The human body uses carbohydrates in the form of glucose. Glucose can be converted to glycogen, a polysaccharide similar to starch, which is stored in the liver and the muscles and is a readily available source of energy for the body. The brain and the red blood cells need glucose as an energy source, since they cannot use fat, protein, or other forms of energy for this purpose. It is for this reason that glucose in the blood must be constantly maintained at an optimum level. Approximately 130g of glucose are needed per day to cover the energy needs of the brain. Glucose may come directly from dietary carbohydrates, from glycogen stores, or from the conversion of certain amino acids resulting from protein breakdown. Several hormones, including insulin, work rapidly to regulate the flow of glucose to and from the blood to keep it at a steady level.
The glycaemic response and glycaemic index
When a carbohydrate-containing food is eaten there is a corresponding rise and decrease in blood glucose level called the glycaemic response. This reflects the rate of digestion and absorption of glucose as well as the effects of the insulin action to normalise the blood glucose level. The body’s response to consuming carbohydrate rich foods is the release of insulin, a hormone produced by the cells in the pancreas which is needed to transport glucose into the cells. The rate and duration of the glycaemic response depends on many factors such as the type of sugar, the cooking method and the person’s metabolism and is measured with the glycaemic index (GI). High GI foods like bread, potatoes and cornflakes cause a greater blood glucose response than low GI foods such as fruit, yoghurt and chocolate. Foods with a low GI are digested and absorbed more slowly than foods which have a high GI.
Many foods that contain sugar also contain a large number of calories and a high fat content. These factors together can contribute to weight gain. Foods that contain added sugars, those that do not occur naturally, also cause weight gain that can lead to obesity. To put it simply, the more sugar added to a food, the more calories it has. Because most of the foods that contain a large amount of added sugar, like soft drinks and desserts, also contain very few if any nutrients, nutritionists classify them as nutrient-poor foods, also known as empty calories. However, sugar is not always a source of empty calories if you consider that you wouldn’t eat a spoonful of sugar; instead, it is consumed with foods that are sources of nutrients such as fruit for example. However, consuming a lot of empty calories means that you cannot get your required nutrients and therefore, sugar in general is associated with weight gain and obesity, a condition that affects nearly one-third of adults in the UK.
Should you choose sweeteners instead?
Although there have been concerns that sweeteners cause cancer there is no scientific research to prove this. Therefore, it could be worth opting for artificial sweeteners, sugar-free gum and low-calorie alternatives if you care about your waistline. It’s totally safe at the levels we regularly consume, and losing weight helps reduce our risk of certain cancers as well.
Brown vs white sugar
It’s a common misconception that brown sugar and honey are healthier alternatives to white sugar. That is not true. Both contain essential minerals, but in such tiny amounts as to contribute nothing to our diet. Brown sugar is white sugar with added molasses which is a black syrup by-product of sugar refining. Fructose, which found in table sugar, honey and high fructose corn syrups used as sweeteners in the food industry, is metabolised differently to glucose. It’s readily converted into fat, raising blood cholesterol level as well.
Carbohydrates are a vital component of a healthy and balanced diet. They can help to control body weight, especially when combined with exercise, are vital for proper gut function and are an important fuel for the brain and active muscles. Fibre helps to ensure good gut function by increasing the physical bulk in the bowel and stimulating the intestinal transit. People who eat a diet high in carbohydrates are less likely to accumulate body fat compared with those who follow a low-carbohydrate/high-fat diet. Neither starch nor sugar has been found to have any special role in the development of serious diseases such as type 2 diabetes. Opt for low GI slow releasing carbohydrates and enjoy the occasional treat as well! So, don’t remove the carbohydrates from your diet as it turns out they are absolutely essential.
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By Kleio Bathrellou
Associate Nutritionist & Certified Sports Nutritionist