Carbohydrate is the main source of fuel for our body and along with protein and fat is one of three macronutrients in our diet. Depending on who you talk to, and what diet they follow, any one of these can be considered ‘good’ or ‘bad’ for your health, and your waistline. In reality, each of these macronutrients are essential. It is just a matter of striking the right balance.
We find carbohydrate in foods like bread, cereals, rice, potatoes, pasta, vegetables, fruits and pulses. Depending on which carbs you chose, they can provide a fast release of energy from foods like sugar, honey, white bread, refined foods, or a more slow and steady release of energy from foods like oats, brown rice, pulses and root veg.
It’s the fibre that makes all the difference. Fibre acts like a buffer to sustain a more even blood sugar balance, which is what you want.
From complex to simple, high GI and low GI, carbohydrates fall into 3 categories:
Choose the fast release, high GI stuff and you’ll end up craving more white carbs and sugar, crashing energy levels and putting on weight. Switch the balance and opt for the low GI, slow release carbs and you will feel more energised, think more clearly and be able to manage your appetite without even trying.
All carbohydrates are made up of the same building blocks of carbon, hydrogen and oxygen to form simple sugars like galactose and glucose, also known as monosaccharides. These monosaccharides join together to form disaccharides (like lactose or sucrose) or polysaccharides (like cellulose or glycogen). The more complex the molecule, the slower it is broken down by your body.
Glucose is the simple monosaccharide unit that we use for energy. If we eat simple, high GI carbohydrates, they are converted to glucose very quickly, to be used as immediate energy, whereas a complex carb has to be broken down by your digestive system and liver before it can be transformed into glucose and used as fuel.
High GI foods act like rocket fuel to give you a quick burst of glucose, and energy straight into your bloodstream. Very quickly your pancreas will release insulin to drive this glucose safely into your cells and store the sugar in fat cells, so shortly after eating chocolate, white bread or half a pack of biscuits, you feel the crash in your mood and your energy levels, leaving you cranky, lethargic and ‘hangry’, looking for another fix of sugar or white carbs to bump your blood sugar back up again, and so the cycle goes on.
On the other hand, low GI carbs that are low sugar and packed with fibre (think wholegrains such as oats or pulses) provide you with a more steady and even supply of glucose that is easier for your body to handle, will help to maintain your energy levels, regulate appetite and curb cravings. The fibre in these foods slows the glucose release and helps to keep you feeling fuller for longer. This fibre found in low GL foods has other benefits too - from helping to support a healthy gut microbiome, to hormone balance and cardiovascular health. Better for your health, energy, mood and weight.
When we bombard our bodies with white, refined and high sugar foods over many years, our cells become less responsive to the effects of insulin, so it gets harder to regulate blood glucose balance, and we can end up with weight gain, inflammation and at a higher risk of type 2 diabetes.
The glycemic index (or GI) can be thought of as a measure of the quality of carbohydrate, but quantity is important too.
Aim for a fist-size portion of low GI carbs, or about a quarter of your plate as a rough guide.
When we eat the right quantity of the right quality of carbohydrate, we have a steady supply of energy and a healthy but balanced appetite.
Jane McClenaghan, author and founder of Vital Nutrition is passionate about the powerful health effects of good food. She founded her business, Vital Nutrition, in 2001 and has helped thousands of people make easy, manageable changes to their diets for the good of their health. Jane takes a down-to-earth, realistic approach to health and nutrition, and her philosophy on health and wellbeing is one of balance - simple, effective changes that can fit into anyone’s lifestyle. Jane specialises in helping workplaces support their employees to eat well, has an online membership for women who want to get their spark back, and is the author of 'The Vital Nutrition Cookbook' and 'Vital Nutrition - eat your way to optimum health, happiness and energy'. She is the resident nutritionist on U105 with Carolyn Stewart and writes a weekly nutrition column for The Irish News.