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You Will Learn

• The difference between different types of sugar.
• Why starch is just sugar.
• Why fructose is worse for you than other types of sugar.
• Why you shouldn’t pay much attention to the debate about sugar vs high fructose corn syrup.  

Much of the information in this post comes from a fantastic book: The Diabetes Code by Dr. Fung. This book explains how to prevent and reverse Type 2 Diabetes naturally and I highly recommend it.  

What is a Carbohydrate?  

A carbohydrate is simply a type of food compound. They are called carbohydrates because at the cellular level they contain carbon, hydrogen, and oxygen. Carbohydrates are one of the 3 major categories of food, also known as macronutrients. 

The other two are proteins and fats. Carbohydrates tend to be our bodies preferred source of energy because they are broken down faster and easier than proteins or fats.  

What are the Different Kinds of Carbohydrates?  

There are 3 major types of Carbohydrates – Fiber, Starch, and Sugar. Each group of carbohydrates has subgroups.  

In this article I will break down the facts about sugar and starch (which as you find out is just more sugar!).  

There are more forms of sugar than I mention in this article but for the average person just trying to learn more about health and wellness, this is plenty!  

Overview

There are 3 main types of monosaccharides:  

1. Glucose 2. Fructose 3. Galactose  

The next form of sugar I discuss are disaccharides, which are 2 of the above monosaccharides joined together.  

The 2 main types of disaccharides are:  

1. Lactose (1 Glucose + 1 Galactose) 2. Sucrose (1 Glucose + 1 Fructose)  

The final form of sugar I discuss is a polysaccharide. These are multiple monosaccharides joined together. 

The main polysaccharide example I discuss is:  

1. Starch (multiple molecules of Glucose)

Monosaccharides

The most basic form of sugar is a monosaccharide, consisting of a single molecule of sugar.

Monosaccharide #1: Glucose  

What it is: Glucose is a single molecule of sugar that is used by every tissue in the body. Some tissues in your body like your brain can ONLY use glucose for fuel. Glucose is also known as “blood sugar” because it circulates freely in your blood. Out of all of the sugars, glucose is most closely related to blood insulin levels. That is why someone with type 1 diabetes or advanced type 2 diabetes frequently checks their “blood sugar” i.e. blood glucose, to see if they need to administer insulin.  

What the body does with it: In his book The Diabetes Code, Dr. Fung describes a great analogy for how the body handles excess sugar. Imagine if you just went to Costco and bought way too much food. You can’t eat it all right now so you put some in the fridge for later. This is analogous to how your body can’t use all the glucose from a high carbohydrate meal right now so it converts the glucose that it can’t use into something called glycogen.  

Glycogen is long strands of glucose that are stored (in limited capacity) in your liver and muscles for quick energy. Think of glycogen as the food in your fridge…it’s on hand in case you need it.  

But the fridge (and your glycogen stores) are only so big. When your body runs out of available glycogen stores it turns the glucose that is left into saturated fat which is then stored as body fat, similar to how extra food goes into the deep freeze.  

The fat storage hormone: The hormone that makes this all happen…also known as the fat storage hormone…is insulin. Carbohydrates cause the greatest insulin response out of all of the macronutrients (remember the 3 major food macronutrients are carbohydrates, proteins, and fats).

Different types of carbohydrates will affect insulin response differently. For example, non-starchy vegetables (which are carbohydrates high in fiber but low in starch and sugar), will not cause a high insulin response.  

However, a meal high in sugar and starch will cause a high insulin response. This insulin then triggers your liver to create and store fat with the extra sugar just consumed if the body can’t use all at once (which unless you are exercising a lot, chances are it can’t).  

It is this saturated fat that the body makes with the excess carbohydrates that are consumed (NOT the fat in the food that we consume), that causes an accumulation of fat in our body tissues and organs, causing them to malfunction and increasing the risk for developing diseases like type 2 diabetes, cardiovascular disease, and dementia.  

While glucose in excess can contribute to this process, it is really the next sugar that I will discuss, FRUCTOSE, that is a bigger problem.  

Monosaccharide #2: Fructose  

What it is: Fructose is the sugar that is found naturally in fruit and is the sweetest naturally occurring carbohydrate.  

What the body does with it: Unlike glucose that can be digested anywhere in the body, only the liver can metabolize fructose. The brain, muscles, and other tissues cannot use fructose directly for energy. Eating fructose does not appreciably change the body’s glucose level. Neither does fructose produce much insulin response directly.  

Fructose, which raises neither blood glucose nor insulin, was considered ‘safer’ other sweeteners for many years. An all-natural sweetener found in fruit that didn’t raise the glycemic index sure sounded healthy. The toxicity of fructose was invisible when looking at the blood glucose levels or insulin response, it only became apparently dangerous by looking at how fructose caused fat accumulation in the liver.  

Fructose on the rise: Fructose consumption has been on the rise in America. In 1900 the average American consumed 15-20 grams of fructose per day, all of it from fruit. High fructose corn syrup was developed in the 1960s and was soon added to almost every processed food.  

In 1994 the average person consumed 55 grams of fructose per day, mostly from processed foods and sugary beverages.  

Fructose is found in many sweeteners as the chart below shows. As you can see, there is not much of a difference between sucrose (table sugar) and high-fructose corn syrup. Both forms of added sugar will contribute to fatty liver, insulin resistance, and the development of disease.

Fructose and Fatty Liver: Fructose is more strongly linked to obesity and type 2 diabetes than glucose.  

Whereas every cell in the body can use glucose for energy, none can use fructose. When we eat large quantities of glucose, such as starches, the glucose circulates to every cell in the body, leaving only 20 percent of it for the liver to metabolize and store as glycogen or fat.  

But when we eat large quantities of fructose (either in fruit or any of the added sugars, some shown in the chart above), it heads straight to the liver which converts the extra fructose into liver fat.  

This fatty liver plays a crucial role in the development of insulin resistance which is a short step away hyperinsulinemia, obesity, and diabetes.  

This means that fructose is more dangerous than glucose.  

Another consideration is that most of the fructose consumed in America comes not from fruit but added sugar. This refinement process strips the protein, fiber, and fat from the food, meaning you can eat a lot of it and not feel full.  

Think about how 500 calories of a potato or broccoli would make you full but 500 calories of sugary pop probably would not, despite the fact that they are both mostly carbohydrate. This is why we can tolerate eating dessert after a large meal…it is mostly sugar so doesn’t fill us up.  

Monosaccharide #3: Galactose  

Galactose has the same atoms as glucose but a different arrangement. It is mainly found combined with glucose in dairy products like milk, yogurt and cheese in the form of lactose.  

Galactose is digested similarly to glucose. Because galactose is mainly found in dairy, its overall contribution compared to glucose and fructose is relatively low, therefore plays a much lower role in the development of disease.  

Disaccharides  

Now that you have a solid understanding of monosaccharides, the rest is cake (pun intended!).  

What it is: Disaccharides are 2 monosaccharides joined together.  

Disaccharide #1 - Lactose

1 Glucose + 1 Galactose: Found in dairy products like milk, cheese, and yogurt.  

Disaccharide #2 - Sucrose

1 Glucose + 1 Fructose: Sucrose is produced naturally in plants, and is refined in mass quantities to produce table sugar.  

Polysaccharides  

What it is: Polysaccharides are many monosaccharides joined together.  

Polysaccharide #1 - Starch

Starch is the most commonly known polysaccharide. Starch is just many molecules of glucose joined together.  

Starchy foods like potatoes, pasta, and bread will be digested in the same way as glucose, your body will use what it needs and store the leftovers in the form of glycogen or body fat. 

Action Items  

• If you are trying to lose weight, try to get your carbohydrates from non-starchy vegetables. Cutting back on glucose and fructose (i.e. sweet and starchy foods) will help you lose weight and prevent disease. 
• Remember...pasta and bread are just longer strands of glucose, i.e. sugar. Extra calories of this will be turned into fat. Opt for spaghetti squash for pasta and try low carb tortillas instead.  

References  

1. Fung, J. The Diabetes Code. Greystone Books. 2018. Chapters 8, 9, 14.  

2. Hormonal Obesity IIIV: Hyperisulinemia and Hypertension Picture: p. 115 in The Diabetes Code.

3. Insulin Response Picture: https://www.diabeticstrong.com/blog/obesity-why-it-did-not-cause-your-diabetes/.  

4. Sucrose and Fructose Picture: http://www.cornnaturally.com/hfcs-scientific-data/HFCS-Nutritional-Equivalencies/Composition.