Carbohydrates - What Are They?
Having looked at the information on happiness someone asked me “what are carbohydrates?” So I though I had better
explain
Our bodies need energy and
glucose is the type of sugar found circulating
in the blood. It provides all of the cells of the body with energy. Every organ
in the body is made up of cells and every cell needs energy.
Where does glucose come from?
Glucose is produced by carbohydrates
like bread, pasta, rice, table sugar, sweets, cakes and potatoes being broken
down in the process of digestion into glucose, which is then absorbed into the
blood.
Understanding carbohydrates
Carbohydrates
are sugars and starches – bread, potatoes, rice, pasta, cereals and sugar. They
provide the energy our bodies need for all its various activities.
Different types of carbohydrate
Not all carbohydrates are the same!
Sugars and Sugary carbohydrates
¨
Sugary carbohydrates are a more concentrated source of carbohydrate.
Examples are white and brown sugar, which are virtually pure carbohydrate and
contain no other nutrients. They are
sometimes called “empty calories” as they only provide energy and no other
nutrients
¨ Sugary foods, such as
cakes, soft drinks and biscuits contain a significant amount of sugar.
¨ It is easy to eat large
amounts of carbohydrates as sugars and sugary foods.
Starchy carbohydrates
¨ Starchy carbohydrate, those
such as cereals and bread, have other nutrients in them alongside the
carbohydrate.
¨ Because the starchy carbohydrates
contain other nutrients as well they are often more satisfying
¨ Depending on the type some
take longer to be digested and absorbed and therefore tend to give more even
blood glucose levels.
Glycaemic Index GI
The rate at which carbohydrates are digested and
absorbed is called the glycaemic index (GI) of a food. These measurements of how carbohydrates
affect blood glucose levels are performed on human volunteers who are given
glucose or other carbohydrates and the blood glucose measured.
Foods with a lower GI help to maintain blood glucose
levels at a more steady level without any peaks and troughs so they assist with
better blood glucose control.
Additionally, due to this blood glucose control they make you feel full for
longer which helps to stave off hunger pangs so can help with weight loss. They
can also make sure your brain has that constant energy supply it needs so it
can make people feel less irritable and also concentrate better.
Sports people find that such lower GI foods help them
to exercise for longer and often refer to them as “slow burning carbs.”
Glucose or items containing it are absorbed rapidly
–indeed this is why it is used in hypo situations for people with diabetes. As it raised the blood
glucose levels rapidly it is said to have a GI of 100.
The GI of different foods can be influenced by
·
The way food is prepared such as the more processed it is the higher the
GI for example fruit juice has a higher GI
·
The amount of soluble fibre reduced the GI so oats and lentils have a
lower GI
·
The actual chemical structure of the carbohydrates in the starch
molecules so for example basmati rice (a different variety ) has a lower GI
than ordinary white rice
·
If foods have been cooked than cooled the GI reduces so potatoes in a
potato salad will have a lower GI than those freshly cooked
·
Tough coatings like are found in seeds will reduce the GI so grain
breads have a lower GI than wholemeal bread
Levels of GI
- Carbohydrates which produce a GI of over 70 are said to have a high GI—These foods obviously include glucose plus white and wholemeal breads and mashed potatoes
- Carbohydrates which produce a GI of between 56-69 are said to have
a medium GI. These foods include sultanas, canned apricots, ice cream and
egg noodles
- Carbohydrates which produce a GI of below 55 are said to have a low
GI. These foods include chickpeas, lentils, green vegetables, sweet
potatoes, green leafy vegetables, plums, apples and pears
Glycaemic Load (GL)
This is a consideration of both the GI plus the
amount of carbohydrate in a food. It is calculated by multiplying the amount of
carbohydrate in a normal portion of a food by the GI and then dividing by 100.
GL levels are
- Low below 0-10
- Medium 11-19
- High 20 plus
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