## Friday, April 19, 2013

### Caught in the hype, Glycemic Index

Back around 2004 I read the South Beach Diet and since it was actually pretty close to what I was already doing I modified my diet more along the lines of the South Beach Diet.  Good carbs, good oils.  I started eating more sourdough, more brown rice and used more olive oil.  I began drinking metamucil before meals.

According to the South Beach Diet people should eat brown rice because it has more fiber and a lower glycemic index than white rice.  Sounds good.  Is it true?

Recently I decided to take a look at the glycemic index of rice on the University of Sydney's Glycemic Index database.  These are the guys who started the GI craze.  That's my understanding anyway and as readers know our ignorance overwhelms us.  For all I know some kid in Siberia actually developed the idea, or maybe an African grand mother.

Open up http://www.glycemicindex.com/index.php and put "Brown Rice" in the search engine and what do we have?

A lot of information actually.  So what is the first thing I do?  Open up a Libre Office Spreadsheet window and copy and paste the info from the pages into the worksheet.  Now we can look at some numbers.

The Average GI for "Brown Rice" is 62.  Pretty high if you ask me.  The low is 39, the high 87.

Libre Office Spreadsheet calculates the Median at 62.  The Median is half way between the MIN and the MAX so in this case the Median is 39+24 or 63.  I'm not sure what is up with Libre Office, maybe they are using a formula similar to the one the government uses for calculating "median income".

The low is from a country specific Brown Rice, Brown rice, high amylose (IR42) rice, boiled 30 min, from the Philippines.  How much rice can they produce on a set of islands?  According to http://www.mapsofworld.com/world-top-ten/rice-producing-countries.html they produce 11 million metric tons of rice per year and are the 7th largest producer of rice in the world.  So are chances must be pretty good of getting that low GI rice?  Not a chance.  The other six countries combined produce around 360 million metric tons of rice.  Most of that is white rice.

IF all things are equal, the Brown Rice we eat is probably the generic Brown Rice listed at item number 11 and 12 from UofS.  The GI is 66.

Medium GI foods run between 55 and 69.  High GI foods run 70 and up so this means Brown Rice is at the high end of the medium range.

Now I have a problem because I know these numbers are not absolute.  That 66 comes with a standard deviation and a range, but, I have no idea what that is.

According to this chart, if I was eating "Chicken Flavored Brown Rice, Uncle Ben's® Ready Whole Grain (pouch)" with a GI of 46 I would be doing a whole lot better.

What is that axiom about packaged and processed foods being bad for you?  I actually agree with that so it really annoys me when a packaged food is "better" than a "whole food".

What about fiber?  Well, we already know that all Brown Rice is not created equal so lets look at the fiber in Uncle Ben's and "typical" Brown Rice.

First off, lets check the serving size which is typically based on volume BUT also includes weight.  Why is that an issue?  Because 1 cup of Uncle Ben's packaged and processed Brown Chicken Rice is 150grams per serving and 1 cup of Brown Rice is 195g per serving, according to http://nutritiondata.self.com/facts/cereal-grains-and-pasta/5707/2

Lets break this down per 100 grams to make this fair.

Uncle Ben's is: 147 calories per 100 grams and has 2.0 grams of fiber per 100 grams.
Brown Rice is: 111 calories per 100 grams and has 2.0 grams of fiber per 100 grams.

I used http://nutritiondata.self.com as an example.  If you check out that page the glycemic load of Brown Rice is 22.  What does that mean?  To calculate the glycemic load we multiply the glycemic index by the number of carbs and divide by 100.  Is that good or bad?

The higher the glycemic load is the more the food impacts a person's blood sugar.

22*100 gives us 2200 and 2200 divided by 45 (carbs in the nutrition information) gives us a glycemic index of 49.  I call "BullShit".

Are we confused yet?

This is pretty typical of "new technology", everyone jumps on board and no one really knows what they are talking about.  I think I will stick with the UofS numbers for glycemic index for now.

What about White Rice?  According to http://nutritiondata.self.com/facts/cereal-grains-and-pasta/5714/2 which does not have an entry for Bismati Rice the calories are 122 per 100 grams and .6g fiber per 100 grams, and the glycemic load is 22.

Interesting, lower fiber and the same glycemic load.

Lets check out Bismati Rice, that should be easier.  Nope, about fifty gazillion different kinds with different info at caloriecount.about.com

Lets try: http://caloriecount.about.com/calories-rice-i77261 which gives us a whopping 349 calories per 100 grams and 1.5g of fiber per 100 grams.

Now lets run a search on "Basmati, white rice, boiled" on http://www.glycemicindex.com/index.php and we have 6 results, the first has a glycemic index of 43, but, looking down the list we can see the longer we cook the Bismati Rice the lower the index.  That is counter intuitive to me, I would think that shorter cooking times would make the grain harder to digest so it would take longer, apparently not.  Bismati Rice has a GI of 43, well below that of Brown Rice.

Don't run out and grab a bag of white rice though, the lowest GI for white rice is 17 and the highest is 94 so you could be really screwing yourself.  Run a search on "White rice, boiled, type not specified" on  http://www.glycemicindex.com/index.php and we have 9 results, running from 43 to 89.  dump the results with a specific cooking time and the salt water results and we have an average GI of 64.4.  Calories vary wildly also so....

On the surface, it looks like Brown Rice may be marginally better for people than White Rice, but, it doesn't look like a big deal.  Brown Rice does have more dietary fiber.

According to Harvard, http://www.hsph.harvard.edu/nutritionsource/fiber-table/ , we are supposed to have 14 grams of fiber for every 1,000 calories.  If we eat brown rice we need 700 grams or around 3.5 servings to achieve that goal.  If we eat white rice we can't achieve that goal, to get 14 grams of fiber we would have to eat 4,000 calories of white rice.

A glass of sugar free metamucil has 20 calories and 3 grams of fiber so if we drink a glass of metamucil and then eat white rice we can meet the goal.

White rice is shitloads cheaper.  A 50lb bag of white rice runs 20 bucks at Costco.