GI who the sweet truth about carbs

I freaked out at a recent business luncheon when I was referred to as "the protein queen". Although I guess there is some truth to this. I'm the first to advocate protein in times of a health or weight management "crisis", mainly because I believe people just aren't getting enough protein on account of their fixation with all things low-fat.

 

But this isn't to say I'm one of those low-carbohydrate fanatics. Sure, there are some instances when lowering your carbs is a wise move, especially if you want to achieve rapid weight loss. But I'm not out to demonise carbohydrates, and I'm certainly not about to give up my bottle of red for the cause! On the contrary I believe carbs to be just as essential as protein and just as essential as fat. It is, after all, PCF (protein, carbohydrates and fat) which we should always be thinking when we attempt that big balancing act of dieting.

 

Just as there are various kinds of proteins with varying levels of quality, so too are there different quality carbohydrates. In determining carb quality, I like to distinguish between the processed or refined carbs from the unrefined. Processed carbs include white flour which is refined wheat (as in white bread, cakes, pastries, biscuits and most breakfast cereals excluding oats). Natural, unrefined carbs include fruit and vegetables, and whole grain foods (like wholemeal bread, oats, barley and brown rice).

 

 

I shocked many a "health fanatic" after my book went to press by insisting that, as far as your body is concerned, all carbs are essentially sugar - doesn't matter which ironman is on the cereal box. But your body takes time to break these sugars down into glucose. It's this process that concerns many people because the time it takes to digest and utilise a sugar for energy is believed to be relative to the amount of insulin released in the body.

 

Insulin is a hormone that can promote weight gain when there is an excess of any one food group, most commonly carbohydrates. When your brain senses there is too much glucose flooding in - more than what your liver can keep in reserve - it signals for the pancreas to secrete insulin. Insulin transports and stores this surplus of nutrients elsewhere in the body as glycogen and body fat.

 

 

It can take time getting your head around PCF and learning how to identify these food group proportions in your meals. So having bedded this down, do we really need a character like GI to come along and confuse things?

 

In measuring the rapidity of glucose absorption, many people refer to the Glycemic Index (GI). The GI is a ranking of foods based on their immediate effect on blood glucose (blood sugar) levels. Carbohydrate foods that break down quickly during digestion have the highest GI ratings. Their blood sugar response is fast and high. Carbohydrates that break down slowly, releasing glucose gradually into the bloodstream, have low GI ratings.

 

Low GI foods have become widely considered as the healthier carbohydrates, due to diabetes research which strongly supports its ability to help control the condition by causing only a small rise in blood sugar. Recent studies from Harvard School of Public Health indicate that the risks of type 2 diabetes and coronary heart disease are strongly related to the GI of the overall diet. The World Health Organisation (WHO) and Food and Agriculture Organisation (FAO) have recommended that people in industrialised countries should base their diets on low-GI foods in order to prevent coronary heart disease, diabetes and obesity.

 

Low GI diets have also been found to improve the body's sensitivity to insulin. After years of excess carbohydrate consumption, your body, as if "jaded" by carbs, weakens its ability to respond with insulin secretion. It is no surprise that in our carb-addicted modern society, diabetes has reached epidemic proportions.

 

 

When taking GI on board, keep in mind that there are no "good" and "bad" carbs - just carbs that are more appropriate at certain times. Just because high GI foods elevate blood sugar, does not mean they should be ruled out altogether. When consumed immediately after exercise or strenuous activity, high GI food help re-fuel carbohydrate stores and improve protein synthesis, enabling better recovery.

 

Another important consideration is that your GI only applies to single foods. It's the overall meal which has the meaningful GI. While the rating normally applies to carbohydrate foods which your body breaks down into glucose, other foods that are high in protein or fat (such as flesh foods, protein shakes, nuts and avocado) act like fibre when included in your meal, lowering the rate at which sugars enter the bloodstream. This means that although your meal may contain a high GI food such as white potato, the presence of lean meat, along with plenty of dietary fibre in a generous salad, can lower the overall GI of your meal, restoring stability to blood sugar levels. Another reason high GI foods need not be shunned completely.

 

 

Be mindful that GI awareness is relatively new in the food industry. Watch out for those familiar terms such as "complex carbohydrates", commonly heard in advertising jingles and emblazoned on cereal packs. These are increasingly recognised as having little nutritional or physiological significance. The WHO/FAO recommend that these terms be removed and replaced with the total carbohydrate content of the food and its GI value.

 

 

So how do you determine a GI for yourself? Only a few nutrition research groups around the world currently provide a legitimate testing service for GI. The Human Nutrition Unit at the University of Sydney has been at the forefront of glycemic index research for over a decade and has tested dozens of foods as an integral part of its program. It has developed an excellent online GI database which enables you to key a single food or combination of foods and compute their GI rating.

 

The glycemic index (GI) of foods commonly uses a scale where glucose = 100. The table below contains averages of those published in scientific literature and The GI Factor (by Dr Jennie Brand Miller et al, Hodder Headline, 1998).

 

Cornflakes                         84
Rice Bubbles                      82
Cheerios                            83
Puffed Wheat                    80
All Bran                              42
Porridge                             46

Snack foods                      GI

Mars Bar                             65
Jelly beans                          80
Chocolate bar                     49

Legumes                           GI

Lentils                                28
Soybeans                          18
Baked beans (canned)      48

Fruits                                 GI

Apple                                 38
Orange                              44
Peach                                42
Banana                              55
Watermelon                       72

Dairy foods                        GI

Milk, full fat                         27
Milk, skim                            32
Icecream, full fat                61
Yogurt, low fat, fruit           33

Soft and sports drinks      GI

Fanta                                 68
Gatorade                           78