All carbohydrates don’t act in our bodies the same way

We’ve all heard of the glycemic index. Many dieters and all diabetics constantly monitor carbohydrate intake. Carbohydrates don’t all influence our systems at the same rate and that can be important for our blood sugar management.

There are several different kinds of carbohydrates. Sugar is what we think of, and that’s the form most ultimately become before being further degraded to provide energy. Sucrose is table sugar, and it hits our system quickly, almost as fast as straight glucose (blood sugar) would. These are simple sugars. Foods with high levels of sucrose, glucose or fructose travel to our blood quickly and stimulate insulin secretion.

Starches come in two main types. There are straight-chain starches, which we call amylose. Amylopectins have branched chains. They are much larger molecules and take longer to digest. Both types are a connection of simple sugars bonded together.

These sugars are joined by alpha bonds. There is another type called beta bonds, and humans can’t digest them. Carbohydrates with beta bonds are commonly called fiber. These components are found mostly in the cell walls of plants.

Fiber is usually broken down into two groups, soluble and insoluble. Both are important for proper digestive system health. We don’t derive energy from them, but they provide bulk to our stools and help our systems run smoothly.

The glycemic index (GI) is a measure of how fast these carbohydrates are broken down and enter our bloodstream. This can directly affect our blood glucose level at least in the short-term. The GI of pure glucose is 100. Foods containing carbohydrates will fall below that number. Highly processed foods generally have a high GI.

Another factor to consider is the glycemic load (GL). It’s a factor of the GI as compared to the total amount of food consumed. Watermelon has a high GI. It is sugary sweet, so it’s not surprising the figure is around 80, but its GL per serving is not troublesome (15). Cucumbers are even more dramatic. The GI is low to begin with, but the GL is practically zero.

Of the fruits, cherries and raspberries have the most favorable GI and GL levels. They’re a great choice for both dieters and diabetics. However, we’re talking about fresh use. A slice of raspberry or cherry pie won’t correlate with that.

An interesting example that often baffles people is that sweet potatoes have significantly lower GI and GL levels than Irish potatoes. Sweet potatoes might taste sweeter, but their sugars don’t hit the bloodstream as quickly and and have the same impact. Fiber content is also slightly higher. Starches in Irish potatoes degrade into sugars quickly.

Juices and sugary drinks hit our systems rapidly and with strong carbohydrate loads. There is no fiber to slow the process down.

I’ve tried my best to simplify the whole process as to the theory and understanding of the significance of carbohydrates in the diet. I’m not a doctor or nutritionist. There are many other factors to consider. I wouldn’t switch from eating blueberries to raspberries simply because the GI and GL values were half. Carbohydrates are only one factor of proper nutrition.



Ted Manzer teaches agriculture at Northeastern High School.

About tedmanzer

I grew up in Old Town Maine and got a B.S. at the University of Maine in Plant Sciences/ minor in Botany. From there I moved to West Virginia and earned a M.S. in Agronomy at WVU. I also met my wife there. She grew up in rural WV as the daughter of tenant farmers who raised cattle and hogs. Their lifestyle at times was one of subsistence and I learned a lot from them. I've always been a foraging buff, but combining my formal botanical knowledge with their practical 'Foxfire-type' background opened up my eyes a little more. I recently retired from teaching high school agriculture after 25 years teaching with my wife. Until recently I wrote a weekly nature/foraging column for the local paper ( I also have written several Christian nature/adventure novels that can be purchased on Amazon in Kindle format. One is a five book family saga I call the 'Forgotten Virtues' series. In the first book, Never Alone (presently out of print), a young boy comes of age after his father dies in a plane crash, and he has to make it alone. The second book, Strange Courage, takes Carl from his High School graduation to his recovery from a nasty divorce. The third book, Second Chances, takes Carl from his ex-wife's death and the custody of his son to his heroic death at age 59. The fourth book, Promises Kept, depicts how his grandchildren react and adjust to his death (this one is not yet published). In the final book, Grandfather's Way, his youngest and most timid granddaughter emerges from the shadow of her overachieving family and accomplishes more in four months than most do in a lifetime. I use many foraging references with a lot of the plants I profile in these articles in those books. I also wrote a romance novel titled Virginia. It is available on Amazon and is a different type of romance from a man's perspective.
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