Posts Tagged ‘glucose’
September 16, 2012 by Johanna Burani
You may have heard or read about the glycemic index (GI) before, but do you really know what it is? what it measures? what it means?
Canadian scientists invented the glycemic index in the early 1980s to measure how quickly carbohydrate-rich foods are digested in the gut. In other words, the GI measures how long it takes a carb to become glucose and drop into the bloodstream. The researchers tested real foods on real people – no mice or test tubes, just normal people – and they came up with real numbers.
Think of any carb: a slice of bread or pizza, an Oreo cookie, a peach. Each of these foods has certain properties that will always belong to them. A peach, for example, will always be round, “peachy” in color, juicy and fibrous. And, because it’s been tested, we know it has a GI value of 28 (low). Its GI value helps to describe the peach as much as its other characteristics.
The actual glycemic index starts at zero and goes to 100 and is divided into three sections: LOW (0-55), MODERATE (56-69) and HIGH (70+). A peach has a low GI value (28) and that means it is slowly released as glucose from the gut into the blood.
There are labs in Canada, Australia, Europe and other places that follow the same strict World Health Organization-approved protocol for GI testing. To date their studies have deciphered the GI values of more than 2000 foods. These values were most recently published in 2008 as The International Tables of GI and GL Values. GI values also may be found at www.glycemicindex.com or www.gilabs.com.
- What is the glycemic index? A numerical chart of carbohydrates.
- What does it measure? How quickly carbs are digested in the gut and released as glucose into the blood.
- What does it mean? The GI tells us if a carb, once digested, enters the blood quickly or slowly. This information can have a profound impact on health concerns such as diabetes, heart disease and weight management.
September 10, 2012 by Johanna Burani
Today NPR highlighted a recent study conducted by David Ludwig, MD of Children’s Hospital in Boston that illustrated the appetite-suppressing benefits of a well balanced low glycemic index (GI) diet. As one of the study’s participants explained, high GI carbs just did not sustain him and he was hungry soon after polishing off a large bowl of mashed potatoes. This is because high GI carbs (like mashed potatoes) are quickly digested in the gut. This causes first a surge of sugar to be released into the blood followed by a rapid drop in sugar levels from all the insulin the pancreas released in response to the mashed potatoes. This roller coaster results in hunger, low energy and causes the body to more readily store calories as fat.
Not all nutrition professionals look kindly on the concept of the glycemic index. As the dietitian who was interviewed for this segment mentioned, there are many variables that may impact on a food’s GI value: the ripeness of a fruit, the under- or overcooking of starches like pasta or rice, the presence or absence of other nutrients in the gut along with the carb (fat, protein, soluble fiber). Thanks to decades of valid GI testing by researchers in many parts of the world, we know these facts to be true. However, this is indeed how we eat. Our pasta at dinner tonight was cooked. The length of time it stayed in the water, the fat-protein-fiber content of the other foods on that same dish are factors that influenced the rate at which our gut is turning that pasta into glucose and releasing it into our blood supply. The glycemic index is telling us what the body already knows!
Category GI Information, Uncategorized | Tags: carbs, David Ludwig. Ludwig, GI Information, GI testing, GI value, glucose, glycemic index, insulin, low energy, low glycemic, low glycemic index, mashed potatoes, NPR, pancreas, sugar levels
August 5, 2012 by Johanna Burani
The body “runs” on glucose, its simplest form of energy. And it gets this energy by breaking down every carbohydrate we eat. So, all the starches we eat (like breads, pasta, potatoes rice, cereals, crackers and baked goods) and all our sugars too (like all sweetened foods and beverages, fruit, milk and yogurt products) fuel the body all day long.
The body is looking for a slow, sustained delivery of this energy because that’s how it uses it: the right amount all the time, not just after eating. A good carb is digested slowly and slowly releases the glucose it becomes into the body for immediate use. There is no gush of glucose into the bloodstream, just a steady trickle of energy, there for the taking as needed. This keeps the body in metabolic harmony and keeps us feeling fuller longer too.
A balanced meal containing good carbs provides the body with a steady stream of the right amount of energy it needs when it needs it. No sugar highs or lows to deal with. The body loves this set up and performs all of its thousands of metabolic jobs effortlessly under these conditions.
What makes a carb “good?”
- It is slowly digested in the gut.
- It is released as glucose into the blood as a slow, steady stream of energy over a prolonged period of time.
- It doesn’t spike blood sugar levels.
- It keeps us feeling fuller longer.
How do we know that the body slowly digests good carbs? Because of the 30-plus years of research on the glycemic index. Studies conducted all over the world have accumulated consistent and conclusive evidence that explains how specific carbohydrates behave in the body. Some are “gushers” and some are “tricklers.”
Much, much more will appear on this blog about the virtues of the glycemic index concept. For now though, let it be said that a good carb is also a low glycemic carb.