Low Carb Diets and Nutrition
Nutrition experts are now warning that the reason the high-protein
low-carbohydrate regime sounds too good to be true is that it is.
Atkins Diet - Long Term Health Risk
Dr Susan Jebb, head of nutrition at the Medical Research Council's
Human nutrition research unit in Cambridge (UK), told a summit in
London that the Atkins diet is medically unsound and a major
health risk.
She said: "We have no idea what will happen in the long term
because no one is evaluating the results of the experiment."
Atkins Diet Advises Against Carbs
Millions around the world have taken up the Atkins diet, which
advocates abandoning carbohydrates like bread, pasta, potatoes,
rice and cereal in favour of extra meat, fish, eggs and cheese.
But nutritionists believe that carbohydrates are such an essential
part of a normal diet that dropping them could be positively
dangerous for your health.
Dr Jebb says: "Carbohydrates provide around 50% of our energy
requirements.
Why Carbs are Essential for Good Health
Dr Jebb explains they are made up of sugar molecules, composed of
carbon, hydrogen and oxygen, and when these are broken down in our
cells, they provide the energy that keeps us warm and moving and
living.
In theory, diet regimes like the Atkins diet work because
restricting carbohydrate intake means the body taps its fat stores
to fulfil its daily energy requirements. Through biochemistry,
fats are converted into glucose (sugar).
Types of Dietary Carbs
Carbohydrates are divided in two types - simple and complex.
Sugars like glucose, fructose and lactose link together like a
chain to form complex sugars.
Fruits, milk and milk products, refined products such as sweets,
table sugar and cakes contain simple sugars. Starchy vegetables,
legumes, rice, pasta, cereals and bread contain complex sugars.
Not all carbohydrates provide the same amount of energy because
the body absorbs and converts simple and complex carbohydrates
into glucose at different rates.
Carbs and Glycemic Index
The glycemic index (GI) measures the speed that a carbohydrate is
turned into glucose over three hours after a meal. A value of 55
or less is low, 56 to 69 is medium and 70 and above is high. These
rates are set against glucose that has a value of 100.
Dr Jebb says: "Simple sugars are absorbed very quickly and they
give you a burst of energy, while other foods release energy more
slowly and steadily.
"Not all complex carbohydrates have low GIs - it depends on the
type of carbohydrate, the way it is processed, and the type of
starch it contains.
"But, in general, the less refined a product is, and the more
intact the grains, the lower the GI. For example, whole oats and
wholegrain breads have lower GIs than cakes and biscuits."
Dr Jebb says that, although the research is still in its early
days, diets with low GIs appear to be healthier.
"Foods with low GIs help you to feel fuller for longer, and so
help to control weight. They certainly reduce fluctuations in
blood glucose levels, which reduces the risk of diabetes."
Unrefined Carbs Best
She recommends choosing foods that are as unrefined as possible,
such as whole oats, pasta, whole grain bread, and long grain rice,
rather than sweetened cereal or pastry. Foods such as yoghurt
should ideally be sweetened naturally with fruit rather than
sugar.
And carbohydrates do not just provide energy. According to Dr
Jebb's colleague, nutritionist Dr Toni Steer, they also contain
vital nutrients.
"They have essential B vitamins like thiamine and folates. A lot
of these vitamins have a role in energy metabolism in the body.
Carb Restriction May Cause Higher Risk of Heart Disease
"Research has also suggested that reducing the intake of folates
may increase levels of plasma homocysteines, which have been
linked with an increased risk of cardiovascular disease."
Dr Steer says the best way to maintain weight loss is with a diet
that is low-fat and high-carbohydrate.
"There is evidence spanning three, four, five and six years that
such diets achieve and maintain weight loss.”
|
