Monday, 14 July 2014

Glycaemic Index and why it's important for your health

The core of the food hourglass message seems to be about how quickly sugars are absorbed by the body. With this in mind, Dr Verburgh has drawn up a simple list of foods that have a low glycaemic index (GI). The GI of a food tells us how quickly the sugars are absorbed into the body through the digestive system. The higher the number, the faster it is absorbed.

Right at the top of the list (or should that be the bottom?) are foods like lettuce, cabbage, broccoli, courgettes, onions, garlic, tomatoes and aubergines. The sugars in these foods take a long time to get into your blood after you have eaten them. If you eat them along with other foods that have a slightly higher GI the release if sugar into your system is moderated. Which mean less insulin peaks, which means the body isn't put under as much strain. 

Still very low in the rate of sugar absorption are, tofu, walnuts , apricots, soya beans, cherries, plums, grapefruit, dark chocolate and fructose (fruit sugar). These all have a GI of about 20 or less. Apples, oranges, peaches and pears have a slightly higher GI, but at between 30 and 35 they are still good. 

If we compare this to the GI of chips which is a massive 95, the foods above are all good. When we eat chips the sugar is absorbed faster than eating granulated sugar. I know it sounds mad, but sucrose, which is the sugar we stir into our tea, has a GI of 70. Mashed potato which you may think would be much better, isn't. It has a GI of 90. That's a faster absorbing food than white bread which has a GI of 70. When we eat chips we might as well inject pure sugar into our veins and wait for our poor pancreas to go into overdrive. Diabetes here we come.

In brief, the carbohydrates to keep away from or at least keep to a minimum are mashed and chipped potatoes, white and brown bread, white rice, biscuits, processed cereals such as cornflakes (a GI of 85, again, higher than sucrose) and crisps. To be eaten with caution are brown rice (60), white pasta (55), wholemeal pasta (50).

Rye flour has a lower GI than wheat flour, and so if you feel you really must eat bread , then rye bread is better, with a Gi of 40. That's getting close to the Gi of citrus fruits. When you have eaten it for a while, its close and nutty texture is far superior to the fluffy, white, tasteless confection that is white bread. Honestly, give it a week or two and you'll prefer it. 

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