Do We Need Carbohydrates? Part II of III

In case you missed it, click here for part I

Types of Carbohydrates

There are 3 main types of carbohydrates:

1. Monosaccharides

2. Disaccharides

3. Polysaccharides

In order for our bodies to use carbohydrates, they must be broken down into their simplest form. Only single molecules can be absorbed through our small intestine, into our bloodstream, and carried throughout the body to where they need to go.

Single molecules of carbohydrates are called monosaccharides (mono = 1; saccharide = sugar).

The three most common monosaccharides are:

• Glucose

• Fructose

• Galactose

Disaccharides are made of 2 monosaccharides (di = 2; saccharides = sugars)

Some examples are:

• Sucrose (common table sugar) = Glucose + fructose

• Lactose (dairy sugar) = Galactose + galactose

Polysaccharides are made of many monosaccharides (poly = many; saccharides = sugars)

Some examples are:

• Amylose (a type of starch) = Glucose + Glucose + Glucose, and so on

• Cellulose (a type of fiber)= Glucose + Glucose + Glucose, and so on (but with a different type of bond)

Source: https://lpi.oregonstate.edu/mic/other-nutrients/fiber

However, to make things simpler, I usually talk about the 3 main types being:

1. Simple sugars

2. Starch

3. Fiber

Simple sugars are made up of one or two sugar molecules and they are either going to be

• Added sugars, or

• Natural sugars

Added sugars are foods like table sugar, corn syrup, invert sugar, maple syrup, honey (yes, maple syrup and honey are considered added sugars - read more about that here), etc. Natural sugars are mainly found in fruits, dairy products, and vegetables.

Starch is made up of many glucose molecules and is found mainly in foods like grains, beans, legumes, and starchy vegetables.

Fiber is made up of glucose molecules as well, but has a different bond than starch and is found in fruits, vegetables (starchy and non-starchy), grains, beans, legumes, nuts, and seeds.

Carbohydrate Digestion

When we digest food, enzymes have to break the bonds of these molecules until they are in their simplest form, monosaccharides. This process actually begins in the mouth for carbohydrates. When we see, smell, or even just think about food, we start to produce an enzyme called salivary amylase (an enzyme that digests starch) in our mouths. This is why if you hold a potato chip, a cracker, piece of bread, etc. in your mouth, it will begin to dissolve without even chewing it!

This is another reason why carbohydrate intake varies between individuals. Some people have more salivary amylase production, making them better at digesting carbohydrates, while others have less, causing them to feel better on a lower carb diet.

When we absorb carbohydrates, they are going to do 1 of 4 main things:

1. Get stored in our muscles

2. Get stored in our liver

3. Be used for energy/bodily functions

4. Get stored as fatty tissue

Simple sugars are very easy to break down and get used by the body because they have either no bonds or one bond, so it is easy for an enzyme to either do no work at all or break that single bond. Once those bonds are broken (digestion), the sugars can be absorbed and utilized or stored. This is why simple sugars are also called fast or quick-digesting sugars.

Consider a pitching machine. Say it pitches one ball right after another at high speed. More likely than not, you, nor I wouldn’t be able to keep up with it, but we’d have to try to hit the balls as fast as we could right after another. This is essentially what happens in our bodies when we consume too many simple sugars. They enter our bloodstreams more or less all at once, spiking blood sugar quickly, and our cells have to take care of the sugar molecules as fast as they can because our bodies don’t love having a lot of sugar in our blood streams at one time.

Starches take much longer to break down because they have many more bonds, which is why they are often called complex carbohydrates or slow-digesting carbs.

Now say the pitching machine sends balls to us at a slower rate, a rate we can handle, and we hit each one as it comes. This is how our bodies absorb and utilize starches. Sugar molecules enter our bloodstream more slowly over a period of time, and our bodies are able to handle them more easily, taking their time getting the sugars where they need to go. It’s less stressful on our bodies without an immediate spike in blood sugar.

But, processed starches, things like white flour, white bread, etc., that have been stripped of their fiber, making the sugars act more like quick-digesting carbohydrates because there is nothing to slow their absorption.

Fiber can't be broken down because we don’t have the enzymes to break it’s specific bonds, but it does contribute to the speed of carbohydrate breakdown and absorption, as well as overall healthy digestion. And because we don’t break it down, we don’t absorb glucose from it, so fiber does not affect our blood sugar or overall carbohydrate intake.

So how does this help me make healthier choices? Learn more in part III!