What do we want to know about sugar? Let's start with, what exactly is sugar? Carbohydrates are sugar. They are broken down to the very basic form of sugar, which is glucose. Our brain, blood and muscles need glucose to survive. So, sugar is not a bad thing in this context, it just gets a bad rap.
To simplify our understanding of carbohydrates as sugars, we can break them into two groups: simple and complex. Simple sugars are monosaccharides and disaccharides. Monosaccharides consist of glucose, fructose and galactose. Disaccharides are comprised of two monosaccharides: maltose is glucose plus glucose, sucrose is glucose plus fructose, and lactose is glucose plus galactose. Of the disaccharides, sucrose (table sugar, corn syrup, etc.) is the "bad stuff." Lactose is our milk and maltose is our beer. The complex carbohydrates are polysaccharides: starches, fiber and glycogen. In food terms, starches are our grains, legumes, tubers and root crops ("GLoaTR"). Fibers are all plant-derived foods. Glycogen is the storage form of glucose, which we eat a very small amount of in meats.
So, if all digestible carbs breakdown to the monosaccharide, glucose, which our body needs, why does sugar get a bad rap? Well, to understand this, we need to understand how our carbohydrates are digested. The simpler the carbohydrate, the quicker it is digested. Complex carbohydrates (polysaccharides) take longer to digest because they need to be broken down to disaccharides and then to monosaccharides. This breakdown process begins in the mouth via the enzyme, amylase. After that, since stomach juices don't contain enzymes to digest carbohydrates, the majority of the work takes place in the small intestine. Now, here's the catch! Fibers linger in the stomach and delay emptying into the small intestine. That's what prolongs digestion and gives us a feeling of fullness. Digestion of simple and complex carbs takes about one to four hours. Only fibers enter the large intestine. Soluble fibers - oats, barley, legumes and citrus fruits ("OBLoC") - can be broken down and used as energy by the colon. These fibers lower blood cholesterol and glucose levels, good news for our heart and insulin levels! Insoluble fibers - whole grains (bran) and vegetables - exit our body. The bad rap part of sugar comes from the fact that when simple sugars are digested rapidly, we get a surge of the hormone, insulin. Insulin is a fat storage hormone. If our muscles, brain or blood don't need the glucose for energy, it goes to our fat depots.
So, what's the message here? Well, I don't think we can completely avoid the simple sugars - I know I can't. But, what we can do is have an understanding about how much simple sugar we are putting in our body and try to balance it by eating sugars that contain fiber and slow down the digestive process.
|We can understand how much simple sugar we are eating.|
Whitney | Rolfes. "Understanding Nutrition." Cengage Learning, 2011.
Newby, P.K., ScD, MPH, MS. "Nutrition Myth Busters: Fact or Fiction?" IDEA Health and Fitness Association, 2017.