Carbohydrates are often demonised in the health and fitness industry as a cause of weight gain and obesity. Because of this, it can be confusing to know which carbs are best to have (and whether you should have them at all). Here is some info about the different types of carbs and what happens when we eat them (warning; here comes the science bit).
What are Carbohydrates?
Carbohydrates are energy foods. They provide 4 kcal/g. They are needed to support our growth and fuel our activity. Carbohydrates are broken down into glucose which circulates in the blood. Excess carbohydrates are stored in the liver or muscles as glycogen. The glycogen in the liver is gradually released to maintain glucose levels in the blood. The glycogen stored in muscles provides fuel for them to do work. However, carbohydrates which are consumed in excess of needs are converted to fat.
There are two types of carbohydrates; simple (sugars) and complex (starches).
Simple carbohydrates consist of one or two molecules with a maximum of one bond which needs to be broken down in order to become their simplest form. Once this process has taken place they are then ready to be absorbed across the gut wall. There are two types of simple carbohydrates; intrinsic sugars and extrinsic sugars.
Intrinsic sugar means that the sugar is locked inside cells. Fruit contains simple sugars found in their natural state within their cells known as fructose and milk contains the natural sugar lactose. These simple sugars are accompanied by good quantities of fibre and other vital nutrients such as vitamins, minerals and phyto-chemicals.
Extrinsic sugars are added sugars which can also be referred to as refined sugars. These sugars are not contained in cells but have been added to foods at some stage. Examples of these are table sugar, soft drinks, sweets, cakes and biscuits. These contain “empty” calories which means that they provide small burst of energy in the form of sugar but very little or no vitamins, minerals or essential fatty acids. They also lack fibre which means they break down much more swiftly which can destabilise blood sugar. These types of sugars should be kept to a minimum in our daily diets.
Complex carbohydrates consist of larger chains of a thousand or more molecules. Because of this, they take longer to break down into their simplest form to be ready for absorption through the gut walls. These carbohydrates contain food components such as vitamins, minerals, protein, fibre and water. Examples of these are bread, pasta, rice, some breakfast cereals, porridge oats and starchy vegetables such as potatoes and sweet potatoes.
What is GI and GL?
Glycaemic Index (GI) is a tool used to inform us of a carbohydrate’s potential to raise blood sugar levels due to the speed it breaks down and glucose is released into the bloodstream. Food which is rated as low GI will produce a more steady and prolonged rise in blood sugar levels while high GI foods will produce a more rapid and high spike in blood sugars. Some examples of low GI carbohydrates are porridge oats, peas and long grain brown rice while some examples of high GI carbohydrates are white bread, chips and jelly babies.
Glycaemic Load (GL) tells us the relative amount of carbohydrate in food. For example, watermelon has a high GI but low GL as it only contains a small amount of carbohydrate per serving. This measure was developed by researchers as they believe that looking at glycaemic index alone may not tell us everything we need to know about a food item’s impact on blood sugar levels. This method takes into account both the amount of carbohydrate in the food and the impact it has on blood sugar levels.
The Bottom Line
To achieve a healthy, balanced diet, it is vital not to cut out whole food groups. We need carbs in our diet in order to function day to day to the best of our ability. They won’t make you fat or kill you. The amount of carbohydrate you should get in your daily diet is individualised and depends on a number of factors. For example, an athlete in training will need more carbs than a sedentary person. Complex carbohydrates breakdown slower so will keep your blood sugar levels stable, will keep you fuller for longer and provide a steady release of energy. This will help if weight loss is your goal as you’ll be less likely to reach for the biscuit tin. They also provide a good amount of fibre which will keep your bowels in working order. Intrinsic sugars in the form of fruit and dairy products (as long as you aren’t lactose or dairy intolerant or have an allergy) will provide vital vitamins and minerals such as calcium and B vitamins. It is ideal to get a mixture of these two carbohydrate sources in your daily diet. Extrinsic sugars – in the form of refined carbs such as white bread and sweet treats – provide little to no nutritional value so should be kept to an occasional treat.
For people who have coeliac disease or a gluten/wheat intolerance or allergy, the tendency is to avoid carbs but there are many substitutes out there in freefrom sections of big chain supermarkets and health food shops and you can still have rice, grains like quinoa and starchy vegetables.
So fear carbs no more and enjoy your scrambled eggs on (wholegrain) toast on me x