Becoming a GI Joe

All carbohydrates have a value on what is known as the `glycaemic index' (GI), which indicates how quickly that carbohydrate is metabolized by the body and converted into glucose. The lower a food's GI, the longer it takes to be converted. Foods with the highest GIs are the ones that will have the most profound and immediate effect on your blood-sugar levels. All the carbohydrates on a weight- loss and insulin-balancing regime should come from the lower ranges.

There are two indexes: the glucose standard, which rates glucose as having a GI of 100 and the white bread standard, which is based on white bread being equal to 100. Other carbohydrates are assigned comparative ratios based on these figures. It doesn't really matter which index you adhere to, for they both give a pretty good - and sometimes surprising - insight into the speed with which certain carbohydrates are assimilated into the bloodstream.

Below are a few GI values of common foods, based on the glucose standard. Of course you are not expected to remember each specific food's value, so to make things easier, opposite are two simple tables showing you how to classify fruit and vegetables into those with a low GI value (under 20), those with a medium value (20-60) and those with a high value (over 60).

Density values

Each carbohydrate can also be evaluated by its density value. This is the amount of usable carbohydrate in relation to fibre and water content - the more fibre and water a vegetable or fruit contains, the less usable carbohydrates it will have. The most dense carbohydrate foods are pulses, wholegrains and starchy vegetables, particularly when they are cooked and their fibre is broken down, these will raise your insulin levels, so always be aware of this. The table opposite contains a list of low-density carbohydrates that should form the basis of your carb intake on a low-carb diet.

Not only do many fruits feature highly on the GI scale, but a few should also carry a carbohydrate density warning sign. Bananas, dried fruit and concentrated fruit juices are all a bad idea if you are trying to balance your blood sugar levels. It is best to avoid these totally until your blood sugar and weight have normalized, and then carefully re-introduce them into your diet.

Focus on fibrous vegetables that can be eaten raw or steamed - the type that lose a lot of water whilst cooking. This will mean increasing your intake of leafy green vegetables, such as Swiss chard, green cabbage, kale, bok choy, rocket, spinach and endive.

The link between carbohydrates and insulin resistance

The hormone insulin plays a major role in the metabolism of carbohydratesand their conversion to energy in the body. When you eat carbohydrates, they are converted into glucose in the bloodstream, which triggers the release of insulin. This virtually escorts the glucose to the body's cells, where it can be used as energy. If there is too much glucose, the insulin turns it into glycogen, which is stored in your muscles and liver ready to be converted back toglucose when it is needed.

However, in the high-refined 'carob' world in which we live, we often have too much glucose floating around in the bloodstream, and then insulin converts it to fat. And our body cells may become so flooded with insulin that they cease to be responsive to it, so the pancreas keeps producing more and more insulin in an attempt to get energy to your cells. This is known as 'insulin resistance'.

Over a period of time, less and less glucose gets used as energy, and more and more gets laid down as fat. Since insulin also sends messages to the brain to tell you that you are hungry, more and more insulin means increasing cravings for carb-laden food.

The only people who are benefiting from refined foods are:

• The dentists who have to patch up your decaying teeth
• The pharmaceutical companies who have to sell you drugs to sort out the symptoms of your ailing immune system and your susceptibility to chronic and degenerative disease
• The food manufacturers, who are only really interested in profit. If you add to this a high intake of caffeine, alcohol, smoking and a lack of exercise, then you will almost certainly be taking a wobbly walk down the road to ill health.

Is it enough just to cut out refined carbohydrates?

Totally banishing all things processed and adopting a healthier diet based on fresh produce is a definite start, but if you have a weight problem linked to insulin resistance, it may not be enough, because if you are still eating a diet that is too high in the wrong sort of carbohydrates — coupled with not eating enough protein or fat to slow down the rate at which these excessive carbs are hitting your blood-sugar levels — you will still have problems. A low-fat/high-carb diet can give you a nasty shock every time you jump on the scales.

The thing to remember is that all carbohydrates have an effect on your blood sugar, and every gram of carbohydrate consumed is equal to one gram of glucose in your bloodstream. So if you are eating more than your body can burn for energy, or can safely store as glycogen in the liver, the rest will be turned to fat.

The key factor in balancing blood-sugar levels and banishing thesymptoms of insulin resistance is controlling your intake of carbohydrates. In order to do this effectively you need to know which ones have the greatest impact on your blood sugar and which do not.

Initially, this will need a little time and effort on your part as you learn about the different sorts of carbohydrates. You may find that the changes you have to make to your diet are quite drastic, but before long — as you start to feel and look better — you will be amazed at how little you miss the wrong kinds of carbohydrates such as processed and sugary foods. Youwon't feel the need to pile your plate high with potatoes and pasta, because your newly balanced blood sugar levels won't be crying out for acarbohydrate fix.

The carb connection

Carbohydrates are a vital part of the human diet - they are our primary source of energy, and in their natural state they are turned into glucose to provide fuel for all the organs of the body.

THERE ARE THREE MAIN TYPES OF CARBOHYDRATES:

1. Simple sugars, or monosaccharides: glucose (blood sugar), and fructose (fruit sugar)

2. Double sugars, or disaccharides: lactose (milk sugar)

3. Complex carbohydrates, or polysaccharides: starches and cellulose (potatoes, rice, grains and dietary fibre).

The simplest carbohydrate of them all is glucose, which is assimilated immediately by the body. The more complex the carbohydrate's structure, the longer it takes the body to convert it into energy - so 'complex' carbohydrates are the slow burners, because they are higher in more complicated sugars and fibre and thus take longer to break down into energy-giving glucose.

So why are carbs the bad guys?

Even though carbohydrates are a vital component of our overall health, there are certain carbs that serve no nutritional purpose whatsoever, and can even cause us harm if consumed too regularly and in large proportions. They are also the main contributors to the escalating obesity problem. So who are these enemies of our health and weight? They are known as refined carbohydrates.

The problems started the minute we began to process our food and strip out the fibre and nutrients from flour and sugar, to make them look appealingly white. In so doing, we made them nutritionally redundant. Food processing removes magnesium, zinc and chromium from flour and sugar - the three minerals that the body needs to metabolize carbohydrates properly. It also drastically reduces vitamins B₁, B2, B3, calcium and iron.

Junk foods made up of refined flour and sugar, plus nutritionally empty processed fats, colourings, flavourings and preservatives, make up 75 per cent of many people's diets. These so-called 'convenience foods' are 'empty' calories, which hurtle into the bloodstream, play havoc with insulin and blood- sugar levels and actually deplete the body of essential vitamins and minerals that are needed to perform other important bodily functions. Processed foods have also been stripped of their fibre content, which is essential for controlling insulin production and protecting the body against diseases such as diverticulitis and colon cancer.

The GI of food: How low should you go?

Just as all kilojoules are not equal, so all carbohydrates are not equal. Extensive and in-depth clinical trials and studies over the past decade or so have brought about what has become known as The Glucose Revolution, which also happens to be the title of a world best-selling book by Australians Professor Jennie Brand-Miller, Kay Foster-Powel and Dr Anthony Leeds.

Carbohydrates always used to be regarded as the main reason for obesity. Regrettably that theory has remained stuck in the minds of many people in the medical profession and slimming industry and to this day many dieters are following low-carbohydrate diets - much to their detriment, as you know.

Well, here is what every dieter should know about starch: forget all that tripe you were taught and start eating your starches, but eat them wisely. Eat mainly starches with a low GI (Glycaernic Index).

The GI of food indicates the way it scores according to its effect on your blood sugar levels. Carbohydrate foods that are rapidly converted to glucose during the digestive process and therefore rapidly increase your blood sugar (glycogen) levels, have high GI values. Carbohydrates that break down slowly, naturally release their glucose into the bloodstream at a slower rate, therefore raising blood sugar levels at a slower rate. At the school we call this the 'carbo speedometer'. Of all foods, refined sugar (sucrose) and glucose have the highest GI, namely 100. All other foods are rated on a scale from 0 to 100 according to their effect on the blood sugar levels, or to put it plainly, the rate at which they drip into your bloodstream.

Much has been said about the incredible weight-loss benefits of the so-called Mediterranean diet. The popular belief is that it works so well because of the good fats found mainly in the olives and the oily fish prescribed in this diet. Yes, that is true. However, the other main reason for its success seems to have been overlooked. In fact, it is probably the most important reason why it is such an effective, healthy and delicious diet - it also offers loads of (and mainly) low GI starches. That includes beans, pulses and pasta to name but a few, Paradoxically, the one flaw in this diet is the fat: too much of the 'good' fat can make you as fat as bad fat does. And on this diet you are allowed to consume far too much of that lovely good fat! Just think of those tables groaning with tappas and antipasti.

That diet aside, following a low GI eating plan will, in my opinion, be the very best you can do for your weight loss efforts, mainly because of the way in which you are able to manipulate and control your blood sugar levels and consequent insulin production.

The main benefits of low CI foods

• They cause a gradual rise and fall in blood sugar levels, thereby causing lower insulin levels, which makes it easier for fat to be burnt and less likely to be stored.
• They assist in lowering blood fats.
• They are more bulky and are therefore more satisfying.
• They reduce the risk of diabetes and heart disease.