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How Carbohydrates affect Weightloss

Pick up a magazine, watch prime-time television, or surf the net and you are bound to see numerous references to carbohydrates and the glycemic index (GI), and in particular their role in a healthy nutritional program.

As the saying goes, “knowledge is power”, and with that in mind, Body Science provides the following information to help you make more informed decisions about using the GI in your own nutritional plan.

What is the GI?

The glycemic index is a carbohydrate ranking system.

Using a scale of 0-100, the carbohydrate is ranked based on its immediate effect on blood glucose (blood sugar) levels.

This allows foods to be compared, gram-for-gram of carbohydrate.

Carbohydrates that breakdown quickly during digestion have the highest GI - the blood glucose response is generally fast and high.

Carbohydrates that break down slowly, releasing glucose gradually into the blood stream, are classed as low GI. Scientists have now measured the GI of about 750 high-carbohydrate foods.

The key to using the GI to reduce body fat is to minimise the amount of high-GI foods and instead eat more low-GI foods.

The reasoning behind this is that low-GI foods are absorbed slowly, which helps control appetite and delay hunger.

Low-GI foods area also considered excellent food choices in terms of nutritional value.

While this is true, consumer should also be aware that combining carbohydrates with protein or fat will significantly change the GI factor.

So, some foods, which should (if you only considered their GI) be avoided or minimised, can be eaten with protein. This is because protein slows the rate at which carbohydrates are absorbed.

Food marketers have known this for some time and use this as selling feature for their products. So, you will find plenty of products now labelled low GI - even though they are full of sugar! This is a case of “buyer beware”.

GI Ranking of Some Popular Foods

Low GI foods

	Roasted peanuts : 14
	All Brand cereal : 42
	Porridge with water : 42
	Carrots : 47
	Carrots : 47
	Sweet Corn : 54

Medium GI foods

	Basmati rice : 58
	Raisins : 64
	Rye bread : 65
	Weetbix : 69

High GI foods

	White bread : 70
	Popcorn : 72
	Baked potatoes : 85
	White rice (steamed) : 98

Sugar comes in various forms, so it’s a good idea to familiarise yourself with as many of these as possible and carefully read food labels, rather than simply relying on product marketing.

Some other names for sugar include:

	Sucrose
	Lactose
	Glucose
	Fructose

The Biological Role of Carbohydrates

Carbohydrates primarily provide the body with energy, as well as various nutrients (vitamins and minerals).

Carbohydrates are converted into glycogen, which is stored energy found mostly in muscle. This is similar to the fuel tank in your car. Your body can tap into these stores when energy is required (such as during exercise).

However, most people eat too many carbohydrates.

We all need a certain amount of carbohydrates (this varies from person-to-person based on various factors, including activity level). However, these days most people seem to be ‘addicted’ to bread/grains, sugar and other starchy foods.

The body's storage capacity for carbohydrates is quite limited, so the excess is converted into fat and stored in your body’s fatty tissue.

Any high-carbohydrate meal or snack generates a rapid rise in blood glucose. To adjust to this rise, the pancreas secretes the hormone insulin into the bloodstream, which lowers the glucose.

Insulin is a storage hormone. Before the agricultural age it was the body’s way of allowing excess calories from carbohydrates to be stored (as fat), in case of famine. Fat is of course stored energy.

However, these days, with so much high-carbohydrate food easily accessible to us 24-hours-a-day, there is little need to prepare for famine – but our bodies do not know this and continue to react the same way when we over-load on carbohydrates.

Here’s another way of looking at it: You have two cash bank accounts. From the main account you pay your bills and regular expenses such as groceries and petrol. Your second account is a savings account.

If your main account has more than enough money to sustain your lifestyle then there would little reason to dip into your savings account - you would only use your savings account if your main account is a little low or empty.

Similarly, if your glycogen stores (energy stores/main account) are always full then there is little reason for the body to dip into its saving account (fat stores).

So if our glycogen stores are always full and we continue to eat carbohydrates, they are transferred to the body’s savings account – its fat stores.

To reduce these energy stores, we must create a deficit in the body’s glycogen stores. This can be achieved through exercise and nutrition. consume When stores are low, then the body will begin using fat as energy, leading to a loss of body fat.

Which Carbohydrates should I Eat?

There are two types of carbohydrate - starchy and fibrous.

Starchy carbohydrates include breads, pasta, rice and cereals. Fibrous carbohydrates are predominantly green vegetables (e.g. broccoli).

The interesting thing about the energy from fibrous carbohydrates is that they are often referred to as ‘negative calories which suggests that they are calorie-free, which is not quite accurate.

The truth is that they are generally so low in calories that the body usually uses more energy than they contain to ‘burn’ them up.

Therefore, it is very unlikely that calories from these types of foods will be converted to fat, which is why they are one of our preferred sources of carbohydrates.

They also are an excellent choice in terms of dietary fibre and nutrients, and are considered an effective alkaline source for the body. This means they can help to off-set high blood-acid levels. High acid levels reduce energy, increase cholesterol levels and make fat loss even more difficult.

Starchy carbohydrates generally produce longer-lasting energy and are much more calorie-dense than fibrous choices.

Most people base their diet purely on starchy carbohydrates, neglecting the importance of fibrous carbohydrates.

If we eat high levels of starchy carbohydrates - which is often the case at night when our metabolisms are slowing down – we increase the likelihood that they will be converted to fat.

It is often suggested that if fat loss is your goal you should consume starchy carbohydrates in the morning and as the day progresses, change to more fibrous choices.

Another option is to choose more organic (i.e. natural) carbohydrate sources rather than man-made sources. For example, rice rather than bread.

What is the difference between simple and complex Carbohydrates?

There are two distinct types of carbohydrates – but there are also two classifications - simple and complex.

Simple carbohydrates are quickly converted by the body to blood-sugar. Examples include glucose, fructose, sweets, and some fruits. These generally have a high GI.

For the most part, complex carbohydrates are slower to convert to blood-sugar (lower GI) within the blood. These include oats, pasta, some cereals and vegetables.

Most of us could probably do with a reduced simple carbohydrate intake and more complex (greens/complex) carbohydrate in our diet. This would improve general health as well as help to reduce body fat.

How do I know what I am buying?

The GI index is a very good guide when choosing carbohydrates, but to be properly armed to make good food choices, you need to become an avid label reader.

Bypass the ‘97per cent fat free’ marketing and read the ingredient list on every product to get a full understanding of what you are really eating.

Labels must (by law) list ingredients in order of content (highest to lowest). So, if sugar is the first ingredient, we strongly suggest you avoid that product.

Take a closer look at the contents of your shopping trolley next time you are grocery shopping and you may be surprised by what you have been eating without realising it.

Remember that excess sugar will be converted to fat just as easily as fat itself.

One of the biggest mistakes people make is not reading the nutritional and energy breakdown properly. For example, your favourite ‘diet food’ may contain 8 grams of fat per serve (30g).

This sounds reasonable, but consider that there are probably three or four servings per package, and it is likely that you will eat more than one serving at a time. So, if you eat the whole packet (four servings = 120g), that’s 32g of fat!

This is why it is best to look at the nutritional breakdown per 100g – this will provide a much more accurate picture of what you are eating.

Some ingredient lists may not make a lot of sense, making it difficult to evaluate whether or not you should indulge.

If this happens, look at the nutritional label and compare the total calories in the recommended serve with the amount of fat calories per serve.

Each gram of fat contains nine calories, each gram of protein and carbohydrate has four calories. To make this process easier, try rounding out each fat calorie to ten.

For example, a product may have 100 calories and six grams of fat per serve. If you round out the fat calories to 10, then multiply it by the grams of fat (six) you will find that 60 calories come from fat. This means more than half of the product is fat!

Label Analysis

Look at total calories per serve (2) - It is much easier to work with smaller numbers. There are four kilojoules to one calorie, so this product has 141 calories per serve. One gram of fat yields nine calories, so round this to ten. Fat total per serve (three) is 3.9 grams, so multiple this by 10 (39 calories). Total calories = 141; fat calories = 39. This means the product has 27 per cent fat per serve - not 10 per cent! Look at the ingredient lists: The second ingredient is sugar, which means the product is high in sugar. Look further down the list and you will see that more sugar has been added in the form of sucrose, dextrose and glucose syrup.

Label Analysis

Bypass this claim and look at ingredient lists. Sugar is the first ingredient, so it makes up most of this product. Sugar has the highest GI rating. Combining foods can change the GI rating initially, but a sugar is still sugar and the body still reacts to it in the same way - it simply takes longer for the sugar to be absorbed. This means that if this food is over-eaten, it is still highly likely to increase fat stores.

Label Analysis

Yes, this product is 99 per cent fat free. But sugar converts to fat (as easily as fat) when levels exceed what the body requires daily. Once again look at the ingredient list. This product is virtually ALL sugar, which can spell disaster if you are trying to reduce fat stores. Also remember these types of products are very easy to eat in fairly large quantities.

Fruit for Weightloss?

There are many benefits to eating fruit – including the taste. Fruit is also a good source of vitamins and minerals, is readily available and easy to eat ‘on the road’.

But how does it fit into the nutrition plan of someone trying to lose some body fat?

You may have heard of fructose, which is fruit sugar. It is often reported that fruit contains plenty of this sugar, but the interesting thing is that it contains more sucrose and glucose than fructose.

Fructose is primarily used by the liver in two ways: as energy (converted to glycogen) or converted into triglycerides (fat).

To convert it to energy - which is what you want – it goes through an enzymatic process via the liver. However there can be a problem if you eat too much fruit in one day as the liver has limited fructose converting enzyme.

The average person can only covert about 50 grams (200 calories) of fructose to glycogen per day - the rest is converted to fat.

These days, fruit tends to be very processed, which can increase its acidity. Most people can certainly do without increasing their blood-acid levels.

All in all fruits has many beneficial qualities, but if fat loss is your primary goal, carefully monitor your intake.

BSC