Dates and the Glycemic Index

So, this post will be a little out of character for me. It concerns two things that I find interesting: (1) common dates, the delicious honey-like fruit of the date palm, and staple of the Mediterranean diet, and (2) the “Glycemic Index,” which is a classification of foods based on the rate at which their Carbohydrate (i.e. sugar) content enters the bloodstream.

In case you wonder why I would care about these subjects, read my last post, on “the Zone favorable” diet system. Now, I love dates. One pitted date (about 24g) is about 2 CHO blocks in the Zone system (i.e. about 18g carbs), and it is super easy to eat. I often eat one or one half of one to quickly round out the carbs in a very high protein meal (i.e. 4 to 5 blocks). Obviously, a date is so dense and sweet, it’s going to have a high Glycemic Index, and should only be eaten in moderation.

But I was curious to know: just how bad is a date? I did an internet search, and was truly shocked! Most on-line lists of the GI of different foods report a GI for dates of “103”… which is like twice that of table sugar.

This number is super puzzling, since the USDA nutrition database records that one pitted Medjool date (24 g) has about 18g of CHO, roughly half of which are Glucose, and the other half are Fructose, and also 10% of them are fiber. Given their composition, dates SHOULD have a lower glycemic index than table sugar, not DOUBLE that of sugar.

Well, low and behold, I did some more digging and I also found a scientific paper on the subject:

http://www.ncbi.nlm.nih.gov/pubmed/12070575

This paper, by researchers from the United Arab Emirates, says that dates should be classified as low-glycemic foods, and that the commonly available commerical varieties all have GI numbers between 30 and 49.7 (three varieties are tested). These numbers are all in fact lower than sugar (58 to 65 depending on the list; compare Honey at 55).

What gives? Why is this ridiculously high number of 103 still being used on so many lists?

If anyone who reads this post cares to respond, your input would be appreciated.

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3 Comments

Filed under Nutrition

3 responses to “Dates and the Glycemic Index

  1. Will Clower

    Hi Matthew,

    I love dates as well, and am a big proponent of the Mediterranean diet. Something I wanted to add, after reading your post, is that the Mediterranean diet is more than just the accumulations of the foods they eat.

    (I have two books on the Mediterranean diet and provide it as a curriculum course at the University level, with research results on diabetes, cholesterol, and weight.)

    You point out the foods eaten by certain diets. But the behavioral habits of healthy eating are critical to make this lifestyle work for you. If you are eating Mediterranean foods, but are gobbling in the car, playing X-box, or in other distracting conditions, you will overconsume.

    When that happens, the geography of your food choices will not help us.

    It is my hope that we will begin to embrace the full extent of the Mediterranean lifestyle, beyond just its food pyramid.

  2. Matthew C. Baldwin

    Thanks Will,

    nice thoughts! I agree that the geographical origins (or traditional cultural home) of a food are no guarantee it is healthy… our own culture is so unhealthy that we constantly overconsume or thoughtlessly consume everything, good or bad. Myself, I’ve recently begun really trying to live differently, by not only being more educated about food, but more thoughtful, conscious, and vigilant about my eating habits.

  3. ~ oCeAN

    Any idea if there is a difference in GI between PITTED dates and DRIED dates ? Whereever I found dates mentioned in relation to GI, it was always DRIED dates. No-where is the GI for PITTED dates mentioned. I wonder if DRIED are HIGH on GI compared to PITTED dates.

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