If you're considering cutting back on carbs make sure you know all the facts first. Nutritionist Jo Lewin discusses the health benefits of 'good' carbohydrates and looks at the pros and cons associated with following a restrictive diet...
An introduction to carbohydrates
Dietary carbohydrates play a central role in nutrition because they are the body’s primary source of energy and are important for the proper function of everything from muscle contractions to brain activity. Carbohydrates are classified into two basic groups: simple and complex:
These include refined carbohydrates, which are rapidly digested and release sugar quickly into the bloodstream. They are good when a quick, readily availble source of energy is required, for instance before or during exercise. However, if eaten too regularly and in large amounts they can leave you feeling unsatisfied and prone to energy highs and lows. Examples include white bread, honey, pastries and biscuits.
These are rich in nutrients and take longer to digest, therefore providing a steady stream of energy for a longer period of time. Eating complex carbohydrates can reduce the chances of feeling fatigued or hungry between meals. The best examples are those that have undergone the least processing such as oats, wholegrains, brown rice, spelt and barley.
Ideally complex carbohydrates should make up the bulk of your carbohydrate consumption, as they are the best source of nutrients and fibre. Simple carbohydrates often lack fibre and may well have been heavily processed.
Some research suggests that excessive consumption of carbohydrates – specifically, simple carbohydrates - can be harmful to blood sugar control, especially if you are insulin resistant, experience reactive hypoglycaemia or are diabetic. Carbohydrate excess, especially consuming too many refined carbohydrates, is sometimes associated with weight gain and increased risk of heart disease and some forms of cancer.
Fruit & vegetables
The natural sugar found in fruit and vegetables is called fructose. While fructose is considered to be a simple sugar, the high fibre content means the body digests whole fruit and veg more slowly than say a biscuit that contains no fibre but high amounts of white sugar. As a result, eating high fibre foods containing simple sugars is thought to have less of a dramatic effect on blood sugar levels.
The Guideline Daily Amounts for a balanced diet currently recommend men eat around 300g and women 230g of carbohydrates a day. People following a low-carbohydrate diet often try to stick to around 20g a day or less.
Ketosis is often a product of low-carbohydrate diet. This occurs when the body’s glycogen stores, which are produced when carbohydrates are broken down in the body, have been used up and protein and fat become the primary source of fuel.
Because food choices are limited, low-carbohydrate diets tend to be low in calories and high in protein and fat. Fruit, bread, grains and starchy vegetables are often limited. The consumption of protein and fat is increased and make up some of the calories that formerly came from carbohydrate sources.
The Atkins diet and The Dukan diet are well-known ‘classic’ low-carbohydrate programmes, while other plans focus sometimes on the glycaemic index of foods. The glycaemic index (GI) is a rating system for foods based on the extent to which they raise blood sugar levels in the hours after they are eaten. The reference point is pure glucose which is scored at 100. The higher a food scores on the GI scale, the more rapidly the carbohydrate (sugar) is released into the bloodstream.
Low-carbohydrate diets can often be low in fibre and therefore constipation and other digestive issues can be a concern when this kind of diet is followed for a long time. Other reported side effects include diarrhoea, dizziness, halitosis, headaches, insomnia and nausea as well as concerns of nutritional inadequacies due to the restriction of such a large food group.
While the exclusion of carbohydrates often means less refined sugar is consumed; a positive for health, following this kind of unbalanced diet is not suitable for everyone. Such strict dietary approaches are not always conducive to long-term health and should be discussed with a GP or qualified health professional before you start.
If you’ve read all the factsand want to include some low-carb options into your balanced diet, our recipe collection has some delicious suggestions, all containing under 10g of carbohydrates per serving:
Jo Lewin holds a degree in nutritional therapy and works as a community health nutritionist and private consultant. She is an accredited member of BANT, covered by the association's code of ethics and practice.
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