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 GI of food: How low should you go? continue...

Insulin and carbohydrates

Your pancreas produces the hormone insulin. Of all foods, carbohydrates stimulate the secretion of insulin most.

Eating carbohydrates with a low GI causes slow absorption of the food and so, slow entry of glucose into the bloodstream, with a gentler rise and fall in the curve. This means that the pancreas is not over-taxed and can produce less, and more consistent levels of insulin.

To recap briefly on what was said in What's wrong with sugar and starch?: if the pancreas is over-stimulated for long periods of time, because of mostly eating foods with a high GI (such as refined starch and sugar), it may become exhausted and insulin resistance or even type II diabetes could develop. Even if they do not cause diabetes, high (and unnecessary!) insulin levels are undesirable and dangerous. And similarly, high glucose levels in the blood are as dangerous. And we know for a fact that it seriously affects your body fat percentage!

It is sensible to know and understand and to remember when next you crave foods with a high GI (such as bread or refined sugar) that insulin plays a direct part in how your food is metabolised. It also determines whether your body will burn fat or carbohydrate to meet your energy needs. And finally, it determines what your body will do with the available energy in your blood - use it, or store it as body fat.

If you can't go low, go without

Which means go without the fatty topping or other additions to the carbohydrates. By now we all know, GI aside, that what we odd to our carbohydrates is usually what adds to our weight. And by now we also know that carbohydrates - either sugar or starch - don't taste as good without those little additions. They require that 'little something' to make them more palatable: cream with the pasta, gravy on the rice, butter on bread, cheese on pizza and of course dollops of cream on meringues. These succulent little extras not only make the food taste more delicious, which makes us eat more of it, but the fat also aids excessive fat gain.

Go slow, go low!

Believe this: if you can control your food intake in such a way that you eat mostly low GI carbohydrates, your weight will decrease steadily and rather satisfyingly. Your health will improve and your moods will be better. You will have fewer mood swings and you will feel less exhausted. Your appetite won't get out of hand and you won't have those dangerous food cravings. You will enjoy a better quality of life for longer and have the energy with which to enjoy it!

These are not unfounded claims - they are provable and based on scientific trials, conducted worldwide by independent universities and medical authorities.

The magical benefits of low GI foods were discovered when clinical trials proved that the GI of food influences the rate at which animals gain body fat and develop abnormalities in insulin secretion. These trials were extended to humans and proved how the GI of food influences sport performance and appetite control. From there it expanded into lifestyle improvement and more effective body weight control and thus the GI revolution was born. It changed the way in which millions of dieters selected and ate their food. It also changed their body weights for life - downwards!

Yet, it is not always possible to avoid the foods we love; and as far as I'm concerned, it isn't advisable either. We are sensual beings and to ignore or not to respect the cravings for foods that please us sensually, is a sure way of falling back into those old habits of bread and honey and chocolates and all the other high GI foods.

The answer is therefore to combine your foods wisely. One can have high GI bread, topped with low GI cooked beans or humus. At breakfast time, for instance, one can have low GI oats with high GI toast to follow, Combined, the overall GI will be lower than simply having toast with jam and cheese or wheat cereal and toast.

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.