1 August 2005

GI Values Update

Carrots and Sticks
One of the most repeated criticisms of the GI approach over the years has been the fact that carrots were being excluded from diets simply because of their high GI value. Note to GI critics—carrots were retested and the new values published three years ago (2002) in The New Glucose Revolution and on (www.glycemicindex.com), so you need to find a new stick. When carrots were first tested in 1981, the result was 92, but only five people were included in the study and the variation among them was huge. This was in the early days of GI testing and the reference food was tested only once. When carrots were assessed in 2001, ten people were included, the reference food was tested twice, and a mean value of 41 was obtained with narrow variation. It was clear that this result was more accurate and the other value should be ignored. This is a good example of the need for reliable, standardised methodology for GI testing. It is also another case for not using the GI in isolation. Carrots are rich in beta-carotene, a plant form of vitamin A or retinol, which we need to maintain normal vision (a deficiency in vitamin A produces night blindness—an inability to see in dim light). Carrots also provide some vitamin C and fibre, so add them to soups, salads, stir-fries, stews, casseroles, cakes and puddings or enjoy them as a crunchy snack.

  • Carrots, Australian (average) GI 41
  • Carrots (average of four studies worldwide) GI 47


Anonymous said...

Can we assume all your comments about carrots in this issue refers to RAW carrots ?

Anonymous said...

This confirms my concern about the usefulness of using mean values for an individual. The original values weren't wrong, they were just for different individuals on different occasions. As an individual my results might be anywhere between the min and the max values. Generally, looking at the raw data, the only GI results I had reasonable confidence in using for myself were those for pasta!

Rowan Eisner, Brisbane

GI Group said...

We tested raw and cooked carrots in the long ago past - not GI testing per se - but glycemic response. Cooking made virtually no difference. This is not surprising because they contain sugars and not starches.

Best - Gi group

GI Group said...

"The original values weren't wrong, they were just for different individuals on different occasions."

This is incorrect. Glycemic index values have been shown to be reproducible at different labs around the world testing the same foods when the *standarised* methods are used. This is clearly explained in our post.

Best - GI Group

Anonymous said...

Hummm... even the new GI numbers for carrots are worse than those reported for chocolate cake with frosting. And rice has a 32% higher GI when cooked in Canada instead of the US and India. Perhaps this whole GI thing is not ready for prime time.

GI Group said...

The take home message is that carrots have a low GI. Comparing the nutritional value of a carrot and chocolate cake is not sensible. While enjoying the occasional piece of chocolate cake is fine, it does not make up part of a balanced diet simply because of its low GI. Cake is high in saturated fat.

Different brands of rice can have different GIs due to the type of carbohydrate found in the rice grain. Basmati rice makes a good low GI choice no matter where you buy it.