Hey guys sorry about the delay. May I present my third installment in the food blogs:
Carbohydrates cover the broad auspice of sugars (for the scientific among us they are called saccharides). Nearly every single sugar comes from plants, except the loner that is lactose. These sugars make up the majority of the human diet and provide the principle energy source for the human body under normal circumstances. Often it is carbohydrates that people actually tend to eat too much of in the modern western diet. Carbohydrates are found in every single variety of food you can think of. However, their quantities change greatly from food to food and the types of saccharides included can change the costs and benefits greatly.
In basic terms there are two types of carbohydrates: simple and complex. The simple sugars are things such as Fructose (found in fruit), Sucrose (found in granulated sugars) and Lactose (animal sugars). Complex sugars are known as starches in plants (and fibre but let us keep this separate for the moment). The one thing these things all have in common is that when digested they give the body its main source of energy. These sugars will form glucose in animals, which is burnt for energy, and through a process known as glycogen synthesis they will create glycogen for storage and use of this energy source in the body.
Aside from the actual process carbohydrate usage in the body carbohydrates are of interest to us because of the huge parts they make up of our diet. In fact, most foods, except animal products,will be carbohydrate dominant. Therefore, most diets in the UK will also be heavily made up of carbohydrates with the rest of the energy for the body provided by the other macro nutrients of protein and fat. Now, according to the government's 3 year food and nutrition survey:
'The DRV for total carbohydrate is 50% of food energy as a population average.
Mean total carbohydrate intakes ranged from 46.5% food energy for adults
aged 65 years and over to 51.9% for children aged 4 to 10 years.' (2011: 56)
These results (for the UK) provide some interesting reading. Firstly, it proves the huge part that carbohydrates make up in the British diet. However, it also shows they don't make up as much in older adults which may be touched upon in later episodes.
So, the reasons, that carbohydrates exist in the body have already come up, yet, why they have turned up in such quantities should be explained further. Simply put, we need a lot of energy to keep our batteries charged and when we exercise we turn to carbohydrates as our first friends. In fact, explosive, short duration sports such as Sprinting etc. use little else. (see a few paragraphs down for more information i.e. keep reading!) It is only at lower intensities and longer duration that other energy sources are mobilized.
With all of this importance placed on them for human energy it is lucky that our diet provides so many variations on a single theme:
Rice
Potatoes
Pasta
Bread
Oats
Sweets
Sugar
Biscuits
Raisins
Cereals
Fruits
etc. etc.
As you can see it covers a lot. Almost everything, if I include any carbohydrate containing foods. Therefore, it is important to differentiate the various types of carbohydrate containing foods and their benefits and potential hazards to a healthy body.
Sugars in general are absorbed by the body at different rates. In fact, there has even been a scale created to show the different rates they are absorbed. This scale is known as the 'Glycemic Index' (GI) and runs from 1-100 with glucose and white bread being at 100 and, apparently, turkish noodle soup (according to the University of Sydney who invented GI) being at 1. This scale includes almost all foods that are absorbed by the body relative to glucose.
Why is the rate of absorption important? Because different rates of carbohydrate absorption have different effects on the human body. Let us look at table sugar for example (GI of 68) which means it is pretty quickly absorbed by the body. Therefore, it has a number of effects. When any sugar is absorbed a chemical called insulin is released which regulates the body's blood sugar level. This determines the amount of uptake and storage of glycogen by individual muscles of the body. Too many sugars and the liver spends its time trying to break down carbohydrates and not fats. These fats will be stored in the body and show an increase in 'bad' (VLDL) cholesterol in the body. Therefore, an abundance of carbohydrates limit the fat burning potential of the body (as it is not needed as a fuel source so can continued being stored) as well meaning that the pounds will increase. Likewise, insulin lows cause problems in that the body will over compensate and not only release fat into the blood stream for energy but also use up the proteins that could cause growth potential to decrease or even lean mass loss. Too much of a good thing anyone? (lots of the insulin information came from Christie Wilcox PHD's helpful blog and McCardle,Katch and Katch, 2001: 10-15)
However, without carbohydrates we have no energy yet so a balance is required. As the GI shows, carbohydrates are not made equal some will cause higher insulin spikes than others (High GI). The effects of this were explained above but the body does have counter measures to this. However, the higher the spike the greater the bodies reaction in the reverse. This rebounding effect is usually an overcompensation and can cause type 2 diabetes. Therefore, it is important to keep low GI carbohydrates coming into your body. This allows for a more constant influx of carbohydrates without the large spikes. Fibre can also help in this situation which will be discussed in a further blog.
Some Low GI carbohydrates are listed below:
Brown Rice
Oats
Nearly every vegetable ever (except some potatoes and parsnips)
Brown Pasta
Hummus
Beans
Sweet Potatoes
High GI
White Bread
Short Grain white rice
Sweets
Cakes
French Fries
Icecream
Both lists could go on indefinitely.....(Lists provided by the University of Sydney)
Carbohydrates are vital to everyone when taken on board correctly as the bodies primary energy source. Consequently, become even more vital for athletes and heavy training individual. For explosive athletes it provides the only anaerobic (without oxygen) source of ATP for the body. For aerobic exercise carbohydrates supply around a third of the energy requirements. (Coyle, et. al., 1993) However, there is another key point for the 'average joe' to understand fat is mobilized for burning by carbohydrates through so there must be a continual source to of carbohydrates for as McCardle, Katch and Katch denote 'fats burn in a carbohydrate flame' (2001:155). So all you budding dieters and 'low carb' enthusiasts remember that!
So we have learnt how important carbohydrates are to individuals, how abundant they are in the diet and the risks associated with too many. Therefore, carbohydrates are probably the biggest indication that balanced natural and un-manufactured diets are the way forward.
Next time we will look at the big one: Proteins. HENCH or maybe not who knows....well actually I do but anyway....
Much Love x
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