Carbohydrates

Carbohydrate is the main fuel for the body.

Unlike fats and proteins, carbohydrate has no other functions in the body than to supply it with energy apart from a small amount of dietary carbohydrate which is vital for the structural basis of D.N.A and other important molecules. Approximately 55-60% of your daily diet should be provided by carbohydrate intake. Most cells in the body use a mixture of carbohydrate and fat for energy, but the brain is only capable of using carbohydrate in the form of glucose. In fact, no matter which form of carbohydrate enters the body it is always converted to glucose before it is utilised by cells.

Carbohydrate exist in nature in two main forms, SIMPLE and COMPLEX, or as they are more commonly known, the SUGARS and the STARCHES.

• SIMPLE = SUGARS foods such as sugar, cakes, biscuits, jams, sweets chocolate.
• COMPLEX = STARCH foods such as cereals, bread, pasta, potatoes, rice and vegetables.

When it comes to purely satisfying the carbohydrate needs of the body there is no difference between either simple and complex carbohydrates and there is no difference in calorie count. Carbohydrates in the form of Sugar or starch contain 4 CALORIES PER GRAM. In that respect sugar is no more fattening that a potato.

So what’s the difference?

There is a huge difference and this difference comes in the form of the nutritional value of both. Sugar is simply empty calories, hence there is no nutritional value to sugar whatsoever, other than energy.

Complex carbohydrates such as seeds, fruits and vegetables contain an array of nutritional benefits such as protein, vitamins and minerals, and most sources of complex carbohydrates provide dietary bulk or fibre in the addition to the nutrient starch, which leaves us feeling full, and is also essential for efficient gut function.

Fibre

Fibre or roughage is simply the skeleton of plants. It is mainly found in the outer walls of plants and seeds and is therefore higher in unrefined foods. Although there are two main types of fibre, SOLUBLE and INSOLUBLE there are many different versions of each type and all with slightly different beneficial effects; it is therefore best to get your daily intake from a wide variety of foods. Fibrous foods help you to feel full for longer and hence reduce the appetite, as well as having the additional health benefits of helping to control blood sugar levels by allowing sugar to be released from foods more slowly.

Insoluble fibres

hold water in the digestive tract thus increasing bulk. This stimulates the muscles of the tract so that they retain their health and tone, preventing illness, constipation, haemorrhoids and more severe forms of bowel problems such as diverticulitis and even bowel cancer.

Moreover, a diet high in natural fibre, with the ability to encourage efficient elimination of waste products, prevents the reabsorption of toxins in the bowel.

Insoluble fibre food sources: Wheat bran, wholegrain breads, cereals and a wide range of fruit and vegetables

Soluble fibre

May have a role in lowering blood cholesterol levels. Although the exact mechanism by which this occurs is not known, it seems that soluble fibre can be partially digested by the bacteria in the gut and some of the products of this digestive process enter the blood stream to cause the cholesterol lowering effect.

Soluble fibre food sources: Oats, beans, legumes, in addition to fruit and vegetables

As with most nutrients it is possible to consume too much fibre. One of the problems is that fibre decreases transit times through the guy (slowing gastric emptying) and therefore may limit the time available for absorption of essential nutrients. Some forms of fibre can actually bind required minerals such as calcium and zinc preventing their absorption.

Current recommendation consumption of fibre – 30 grams per day

In America it has been estimated that the average daily intake is approximately 12 grams. As British diets are very similar in terms of their consumption levels of refined foods, fats and simple sugars, it would seem that we are in very little danger of over consumption and would benefit enormously from an increased intake of complex and unrefined carbohydrate.

However if you do consume too many calories over and above your daily needs and they are carbohydrate calories, this is better than if they were fat. This is because, although they are both stored in the body as far, some energy is used to convert the carbohydrate to fat. Because of this an over-consumption of 300 fat calories will lead to storage of 300kcals of fat. An over-consumption of 300 carbohydrate kcals will only lead to about 230 kcals of stored fat. This is obviously important information for those who are concerned about weight control.

Whilst there are no known clinical conditions caused by an over consumption of complex carbohydrates, there are however, problems associated an over consumption of simple sugars, such as the development of type 2 diabetes (also known as Maturity Onset Diabetes), dental cavities and obesity.

Diabetes is an extreme form of blood sugar imbalance. This condition arises when the body can no longer produce sufficient insulin. The result is too much glucose in the blood and not enough for the cells. The effect of carbohydrates on blood sugar will now be discussed.

Blood Sugar

Carbohydrates are basically sugar; the type of sugar, either simple or starch, depends upon the type of carbohydrate eaten. When you eat complex carbohydrates such as whole grains, vegetables, beans or lentils, or simple carbohydrates such as fruit, the body does exactly what it is designed to do; it digests these foods and gradually releases the potential energy, resulting in healthy, even balanced blood sugar levels. However, consuming too many simple carbohydrates has a very different effect upon blood sugar levels.

Why?

The level of sugar (glucose) in the blood is under the control of a pair of hormones called insulin and glucagon. Both are manufactured in the pancreas, which lies just behind the stomach. The pancreas secretes insulin into the blood stream when carbohydrate has been eaten; the insulin travels to the liver and the muscles, instructing them to take glucose from the blood stream and to store it as glycogen. As insulin levels increase, blood glucose levels start to fall, but when this reaches a critical low level, it causes the brain to send for more supplies. The brain cannot exist for long without glucose. If these instructions from the brain are ignored or slow to be fulfilled you begin to suffer the symptoms of Hypoglycaemia, the first of which is mental fatigue.

The reason for this is because the levels of insulin in the blood are still high, perhaps because you consumed too much carbohydrate (High GI foods) within your last meal, which will prevent the release of more glucose. Under normal circumstances (where carbohydrate is properly balanced with protein) the production of insulin is not excessive, and the range over which blood sugar moves is minimal. In this case when a small drop of glucose occurs, the hormone glucagon is released from the pancreas and this hormone stimulates the breakdown of glycogen stores in the liver to release glucose into the blood again. So we can see that insulin and glucagon have opposite effects, and the balance needs to be finely tuned to keep blood sugar stable.

So, an over consumption of simple carbohydrates such as sweets, cakes and biscuits will cause a much more rapid release of sugar (glucose) into the bloodstream, thus causing blood sugar to rise too high too fast; this then irritates the pancreas which responds by producing extra insulin to cope with the extra rise in blood sugar. Cells only take in glucose as needed, so the fat cells open their receptors (doorways) too soon and blood sugar falls rapidly to very low levels, subsequently producing bursts of energy followed by slumps in energy. One then tries to counteract this slump in energy by eating more food, which is not needed, and is therefore stored in the body as fat, and results in weight gain. Therefore balancing blood sugar is probably the most important factor in maintaining even blood sugar levels and weight.

We can learn about the speed at which certain carbohydrates release their sugar into the bloodstream via the glycaemic index.

The Glycaemic Index

The Glycaemic Index (GI) is a guide as to how quickly certain carbohydrates release their sugar into the blood system. The HIGHER up on the Glycaemic list the GREATER the effect upon blood sugar, the LOWER down the effect is lessened. It must be remembered though that just because certain foods are high up on the index it doesn’t automatically make them “bad” foods.

For example; baked potatoes which appear “high” on the index and will therefore elevate blood sugar quickly also contain Vitamin C, B1 and Dietary Fibre, but by eating them with baked beans which appear “low” on the index, the effect on blood sugar is evened out by the combining of these foods.

The Glycaemic Load (GL) is a ranking system for carbohydrate content in food portions based on their glycaemic index and the portion size. Glycaemic load or GL combines both the quality and quantity of carbohydrate in one number. It’s the best way to predict blood glucose levels of different types and amounts of food.

The formula is:

GL = (GI x the amount of carbohydrate) divided by 100

e.g. A medium sized apple has a GI of 40 and contains 15g of carbohydrate

(40 x 15) / 100 – g (GL)

High GI foods can increase the potential of body fat and obesity. This then carries risk factors of type 2 diabetes and associated risk factors of numbness in fingers and feet, eye problems and high blood pressure. High GI foods can also have peaks and troughs in energy levels which can lead to lethargy and poor concentration (as already identified). Many other factors impact GI, such as cooking methods and the mix of foods eaten in one meal.

GI and GL Table

Carbohydrate requirements in different groups.

The Athlete

Many considerations for carbohydrate requirements and athletes are discussed later. AS already established, carbohydrates, in particular complex carbohydrates, should comprise the majority of your daily diet, and they are your biggest energy provider.

So it makes sense that if you are a training athlete you are going to require more energy, hence more carbohydrates.

Most people require 5-6g carbohydrate/kg of body weigh daily.

This figure may rise to 8-10g carbohydrate/kg of body weight for those involved in endurance/heavy training programmes.

It is wiser to divide this intake into several meals, snacks and beverages throughout the day rather than one or two overloads.

In practice then, the average female exerciser weighing 50kg would require 250-300g of carbohydrate daily. The endurance athlete weight 70kg would require 560-700g of carbohydrate daily.

The Very Young

What you feed your child to a large extent determines their health and dietary habits for life. Children grow at alarming rates and demands for quality nutrition are high.

Vitamin A is required for protection, Vitamin B complex for energy production, growth, brain and nerve development; Vitamin C for their immune system and skin development; calcium and magnesium for healthy bones and teeth; and zinc for DNA and growth.

These essential nutrients can be found in abundance in a variety of fruit and vegetables; therefore complex carbohydrates should still make up the bulk of the child’s diet.

Energy is essential to a child, and as stated before, carbohydrate is the biggest source of energy.

Insoluble fibre holds water in the digestive tract, increasing its bulk, thus stimulating the muscles of the tract so that they retain their health and tone and prevent constipation (increasingly common in many children due to too many simple carbohydrates in the diet and not enough complex carbohydrates).

The taste for sugar is often acquired at a very young age, with damaging consequences. Too many sugar drinks, sweets, biscuits and cakes, are being given to children, which can give rise to childhood obesity, hyperactivity and dental cavities. To avoid or change this desire for sweetness, sweetened drinks should be replaced with fruit juices diluted half and half with water. Among the fruit juices, apple contains teh slowest releasing sugars, which grape juice contains the fastest releasing ones. So apple juice is preferable.

Sweets and cakes should be eaten in moderation and not at the expense of other more essential nutrients.

Very few breakfast cereals are actually sugar free. Food manufacturers help children to develop a sweet tooth at an early age; most processed cereals contain fast releasing sugars and have added sugar. Instead children should be consuming sugar free cornflakes, oats or millet flakes, sweetened with fruit such as banana or raisins.

The Elderly

The body is designed to work properly on complex carbohydrates such as vegetables, lentils, beans, fruits and whole grains.

These foods when properly digested produce a more consistent level of energy. As we age we may need greater amounts of essential nutrients both to combat the wear and tear of an aging metabolism and digestive system and to counteract the nutrient-depleting effect of medication.

To complicate manners, calories intake conversely needs to be reduced as we age. Therefore a diet high in complex carbohydrates works two fold. First they can provide ample amounts of essential nutrients and secondly they are low in fat and calories.

The post Introduction To Carbohydrates appeared first on CMS Fitness Courses.