After years of protein rich Atkins type diets advertised by the media and diet doctors, many nutritionists seem to focus their advice onto carbohydrate rich diets. Yet they are not talking about increasing the amount of sugar which belongs to the group of carbohydrates they are advising us to increase fibre intakes and ever more food companies create cereals, breads and other products which claim to be high in fibre or to be whole grain.

Fibre is part of the large group of carbohydrates and is a complex carbohydrate. Complex carbohydrates are starches and fibres, whereas sugars such as sucrose (white sugar) or fructose are simple carbohydrates. The major difference between simple and complex carbohydrates is that simple carbohydrates are easily digested and broken down by your body whereas complex carbohydrates are more difficult to be digested and some cannot be digested at all.

Simple carbohydrates are fairly short chains of sugars and complex carbohydrates are very long and sometimes interconnected chains of sugars. Bacteria in the gut play an important role in the digestion of complex carbohydrates. The speed of digestion also influences sugar levels in the blood, which means simple carbohydrates cause blood sugar levels to increase quickly whereas complex carbohydrates will influence blood sugar levels slowly and more consistently.

Most fibres are found in plants were they are the structural support of the cell walls such as the kernel of a sweet corn. Hence high fibre diets usually include high amounts of whole grains, fruits and vegetables and low amounts of processed foods. As fibre is indigestible it carries no calories, as such it is even more surprising that nutritionists and dieticians appear to be so keen on increasing fibre in the diets of their clients. One explanation for this drive might be that a large proportion of the UK public is consuming less than the recommended 25-35g of fibre per day.

Yet what does fibre than add to our diet and why is it so important? Fibre adds bulk to your meals. This means fibre rich foods are often lower in energy. More importantly fibre rich foods help to give you a feeling of fullness because they are harder to chew, hence it takes longer to eat them and your brain has more time to register that you are full.

But this is not the only way fibre rich diets help you to feel full for longer, fibre swells in your stomach and takes much longer to pass through the digestive tract which means your urges to eat are delayed. Other suggested health promoting aspects of fibre rich diets are that fibre contains commonly pre-biotics which feed your gut micro flora and therefore could help to boost your immune system and fibre rich foods are also full of vitamins, minerals and antioxidants. Finally fibre is thought to aid the binding of cholesterol and therefore helps to balance cholesterol levels.

There is another important aspect to know about fibre. Fibre comes in two different forms in our foods soluble and insoluble fibre. Soluble fibre becomes gel like if liquid is added. Hence soluble fibre swells in our stomach to a gel, which influences the binding with cholesterol and other fats in the digestive tract as mentioned above. Insoluble fibres on the other hand pass through the digestive tract without forming gels. They are believed to be highly beneficial to manage diabetes, constipation, haemorrhoids and appear to prevent some cancers.

However because most people’s diets are low in fibre increasing fibre in the diet may need some consideration. People opting for higher fibre intakes should assure to increase their liquid intakes to avoid getting constipated. It is also advisable to gradually increase fibre intakes to avoid bloating and wind, which often occurs alongside increased fibre intakes. The reason for these side effects are often a not well adapted gut micro flora so it will take some time for the gut micro flora to change and adapt to the new diet.

Although all plants are good sources of fibre, food particularly rich in fibre includes pulses (lentils, chickpeas, and dried beans), nuts and seeds, whole grains and cereals. If you aim to increase fibre intake also try to eat fruits and vegetables with skin/whole and chose regularly raw fruits and vegetables as cooking reduces the amount of fibre in fruits and vegetables.

Fibre has clearly become an interesting tool for the food industry, with ever more foods claiming to be high in fibre and whole grains to make us buy more of their products. While there is evidence that fibre has beneficial effects we need to remember that many other aspects of our diet and our daily lifestyle choices will influence our future health and therefore increasing your fibre intakes while sticking to other unhealthy habits may not be enough to prevent future health troubles.

Andrea Zick – Esteem Fitness Nutritionist
Esteem Fitness – Personal training London and South East UK