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Table of Glycemic Index (GI) and Glycemic Load (GL) food values - 2002
Simple List of GL foods
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What's GI?
There has been much talk about the Glycemic Index (GI), the measurement of how rapidly a particular carbohydrate turns into sugar, by many low-carb dieters and diabetics alike. Not all carbohydrates are created equally. Some turn to sugar more rapidly then others, causing a spike in insulin, while others are slower, causing an equally slower rise in insulin. The GI measurement is based on a reference of 50 grams of glucose (or some tables use white bread). The higher the GI value, the faster it turns to sugar.
But that’s not the whole story. GI doesn’t take into account the amount of the particular carbohydrate in a serving of food. It simply compares 50 grams of carbohydrate “X” against 50 grams of glucose. So, carrots for example have an extraordinary high GI of 131% (50 grams of the carbohydrate in carrots turns to sugar 131% faster than 50 grams of glucose). Does that mean a low-carber should avoid carrots? Absolutely not.
What's GL?
Enter the Glycemic Load (GL). This takes into account the serving size of a particular food. For instance, a ½ cup of carrots has a high GI of 131%, but the amount of carbohydrate in this serving size is only 8 grams. Therefore, the GL is 10.48 (1.31 x 8 = 10.48). This is relatively low, compared to a baked potato, which has GL of 45, or a ½ cup of cooked white rice, which has GL of 28.
NBA to the rescue
Confused? Okay, this might help. Most of you know Kobe Bryant, LA Lakers' super-star basketball player (sorry Shaq, this is just an example). He averaged 25.5 points per game, 5.5 rebounds per game, 5.5 assists per game, and was recently named to the All-NBA First Team. In other words, if Kobe was a carbohydrate, he would have a GI of 200%. Would the Lakers be guaranteed a championship season? Maybe not.
Consider if the rest of his team, Team A, was composed of “Mr. Brick” and “Mr. Butterfingers.” Even though, Kobe has a superstar GI number, the rest of the team are duds, and have low GI numbers, say 0%. Sure, Kobe would still do his stuff, but the rest of team would trudge along at the best of their meager abilities. Team A would have GL of only 2 (200% x 1 player = 2).
Across town, there is Team B, whose best player is only half as good as Kobe, a GI of only 100%. But the rest of the team is just as good, with equal GI’s of 100%. Individually, Kobe would just blow them away, but as a team, they could do some damage. Assuming the team has 5 players, their GL would be 5 (100% x 5 players = 5). With a GL of over twice as high as Team A, they might just mop the floor with them.
Or, if you could clone Kobe five times, you could create a Team C with a whopping GL of 10 (200% x 5 players = 10). Now, that would be a team with an insulin spike!
NBA example summary:
| Team |
GI |
GL |
Insulin Impact |
| A |
200 |
2 |
low |
| B |
100 |
5 |
medium |
| C |
200 |
10 |
high |
Sum it up
So what’s it all mean? Well, check out the table. The GI is a useful number, but the GL number is a more practical number. See how Team A has a high GI, but it actually has the lowest insulin impact. That's because the GL is the lowest. The GL just doesn’t look at the individual carbohydrate, it looks at the total amount in a serving. This would be similar to carrots -- high GI, but not a lot, so it has a low GL.
In fact, a lower GI carb could have a higher impact on insulin simply because there is more of it per serving, like in Team B. This would be like rice. Rice has a GI of 81% (less than a carrot), but the same 1/2 cup has GL of 28 (more then 2.5 times greater then a carrot).
Lastly, if you get a high GI carbohydrate and a lot of it, it will have the greatest impact on insulin, like in Team C or a potato (121% GI and a 45 GL).
| Food |
GI |
GL |
Insulin Impact |
| Carrot |
131 |
10 |
low |
| Rice |
81 |
28 |
medium |
| Potato |
121 |
45 |
high |
The moral is: GI can be misleading. GL is an easier measurement to follow. Low GL foods have a lower insulin impact. High GL foods have a higher impact. Eat low GL foods to maintain your HPLC diet.
That’s my sports story for the day. It reminds me of the movie “Big” when Tom Hanks tries to explain math. It seemed to work for the kid. I just hope it works for you.
References
The Harvard Women's Health Watch, "Glycemic Load, Diet, and Health," Feb. 2, 2002.
Martin, M., "The Load Lowdown," Seattle Times, Sept. 16, 2001.
Liu, S., Willett, W., et al, "A prospective study of dietary glycemic load, carbohydrate intake, and risk of coronary heart disease in US women," American Journal of Clinical Nutrition 2000; 71:1455-61.
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