At lunchtime recently, several of my colleagues claimed that carrots are "full of sugar." Is that true?
In a word, no. That myth gained popularity a few years back when carrots were branded as restricted foods in several popular diet books. The reason? Those diets were at least partially based on the glycemic index, and, originally, at least, carrots landed pretty high in that listing.
The glycemic index, or GI, measures how much and how fast a food raises blood sugar levels after it is consumed. The idea is that you want to prevent frequent spikes in your blood sugar, which provoke the release of high levels of insulin. Insulin is necessary because it allows sugar to leave the bloodstream (where it can cause damage if it remains too long) and enter cells where it can be used for energy. But chronically high levels of insulin are linked to the body's cells becoming resistant to insulin, and that's associated with the onset of type 2 diabetes. So, the thinking goes, to prevent insulin resistance from developing, you need to reduce the occurrence of blood sugar spikes, and you can do that by focusing on foods with a low glycemic index rating.
Foods low on the glycemic index (55 or below on a 100-point scale) are digested more slowly, causing more gradual rises in blood sugar and insulin levels. There's some evidence that this helps control the appetite and delay hunger.
But, back to carrots. According to "GI News, The Official Glycemic Index Newsletter" (online at http://www.glycemicindex.com) the reputation of carrots as a high-GI food began in 1981, in the early days of glycemic-index testing. There were some flaws with those tests, though, and cooked carrots landed high on the scale. In the 1990s, when GI testing was standardized internationally, carrots were reexamined and their GI fell to a respectable 41. It seems word hasn't gotten around to all corners, though.
Since the glycemic index isn't listed on labels, it can be difficult for consumers interested in choosing more low-glycemic foods. You can use online databases, such as the one available on http://www.glycemicindex.com, or pocket guides that are updated every year or so. Or, just use some standard tips from the Web site:
- Choose breakfast cereals based on oats, barley and bran.
- Choose breads made with whole grains, stone-ground flour or sour dough.
- Cut back on white potatoes, but enjoy plenty of other fruits and vegetables.
- Choose Basmati rice; avoid Jasmine rice.
- Cook pasta al dente (firm); overcooking boosts its GI.
- Choose reduced fat dairy products.
Chow Line is a service of Ohio State University Extension and the Ohio Agricultural Research and Development Center. Send questions to Chow Line, c/o Martha Filipic, 2021 Coffey Road, Columbus, OH, 43210-1044, or firstname.lastname@example.org.
Editor: This column was reviewed by Carla Miller, associate professor of human nutrition in the College of Education and Human Ecology.