Copyright (c) 2007 Ainsley Laing
"You might as well eat the box. IT has more nutrition than the cereal inside". These are the words of my mother every morning when I was a kid.
Of course, that was the 1960s which was the real beginning of the popularity of pre-prepared convenience foods. Nutrition science was more geared toward preventing beri beri than promoting health and longevity.
Nutrition science has come a long way since then and provides you new tools as the Glycemic Index (GI) and the Glycemic Load (GL)
What is the Glycemic Index (GI)? The Glycemic Index is a ranking of foods based on how they affect blood glucose (sugar) levels. Since protein and fat don't really impact blood glucose, it's really an index of the rate that carbohydrates are broken down in the gut and enter the bloodstream. The higher the GI number, the faster it goes into the blood.
Eating high GI foods triggers an insulin mechanism which causes the body to store fat. For most of us, eating a lot of high GI foods causes an increase in fat storage.
Most beans, whole grains and non-starchy vegetables have a low glycemic index; while sugars, foods made from refined flour (eg., white bread), most fruits and some root vegetables have a high GI.
The more processed, cooked or chewed a food is, the higher the GI because the gut doesn't have much to break down. Soluble fiber, like in beans slows down the release of carbohydrates in the blood. The degree of ripeness of a fruit: more ripe = higher GI. Acidic foods, like lemon juice and vinegar slow release of sugar. Salty foods increase the rate of release. Protein in a meal will lower the overall GI of the whole meal.
What is the Glycemic Load (GL)? Now, if you take a look on the web at one of the many glycemic index listings available, you will notice that carrots have a very high GI almost as much as sugar! That does seem a bit odd. Enter the concept of glycemic load index (GL).
The GL takes into account not only the type of sugar (how quickly it spikes blood sugar) but also the amount of other stuff in the food that doesn't affect blood sugar - like water and fiber. There is a mathematical calculation which I won't bore you with.
For example, a half-cup serving of carrots has a GI of 131 (very high) but since it is mostly fiber and water has only 6.2 grams of carbs. The glycemic load of that portion size is 6 (low GL). By contrast, a plain five-ounce bagel has a GI of 72 (high) and has 65 grams of carbohydrate. Its glycemic load is very high at 47.
How Is This Useful? The GL index is a recent development and is still mostly used by diabetics to balance the blood sugar release of whole meals. The GI, which was developed in the early 1980s, helps diabetics manage nutrition, but endurance athletes also use it for "Carbo Loading". It is common for athletes to use low and medium GI foods before an event and high GI foods during and after the event to fuel the muscles quickly for recovery.
The Bottom Line? Eating low on the GI is an easy way for all of us who want to keep our body efficiently using fat rather than storing it and to keep our energy levels consistent throughout the day.
If you don't want to confuse yourself with GI and GL food tables, you can adopt "Anti-Aging Fitness" nutrition plan. The "white list" is low GL/GI. The "black list" is high GL/GI and the "grey list" is medium GL/GI. Easy to remember and follow.
Happy and healthy eating!
References:
www.healthyeatingclub.com/info/articles/diseases/glycaemic-index.htm www.drweil.com/u/QA/QA326589/h www.drmirkin.com/nutrition/9566.html www.mendosa.com/gilists.htm
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About the Author:
Ainsley Laing, MSc. has been a Fitness Trainer for 25 years and writes exclusively Body for Mind eZine. She holds certifications in Group Exercise, Sports Nutrition and Personal Fitness Training. To see more articles by Ainsley visit
http://www.bodyformind.com or the blog at
http://www.bodyformind.blogspot.com
