HEALTH, NUTRITION 17th January 2018

We’re still confused about Sugar!


Glucose, fructose, sucrose, carbs – sugar comes in many forms, but what exactly is the difference, and is one sugar any worse for you than the other? Let’s find out.

A lesson in chemistry

Sugar is a carbohydrate, used to fuel the human body. Carbohydrates are structured as either monosaccharides or disaccharides.

Monosaccharides are when one type of sugar molecule exists. Glucose and fructose are examples of monosaccharides. A disaccharide is when two molecules of sugar combine. Sucrose is a disaccharide because it requires the combination of glucose and fructose.


This is the most important monosaccharide as it’s the body’s preferred energy source.

Glucose circulates in the blood, hence is also referred to as blood sugar. When you eat carbohydrates like starchy vegetables, bread and rice, the body converts them into glucose to be used immediately by your muscles before physical activity, or stored in the liver for use later on.

When you eat foods converted into glucose, the hormone insulin is secreted to prevent elevated glucose levels in your blood.


Fructose sugar is naturally found in fruits and vegetables, but is added to soft drinks such as fruit juice and soda. Unlike glucose, fructose is only metabolized in the liver and is not the body’s preferred source of energy. Because it does not circulate in your bloodstream, insulin is not required to control fructose.


The most common form of sucrose is table sugar. It’s produced by sugar cane or sugar beets which consist of 55% fructose and 45% glucose. Processed foods (cookies, candies) are high in sucrose, which means your body takes a hit of glucose and fructose at the same time. Whilst glucose is delivered to every cell in your body, fructose stays in your liver.

Fructose: the most dangerous of them all

Doctor Robert Lustig, an endocrinologist at the University of San Francisco believes fructose is toxic to the human body. Why?

Consider this: apple juice contains four times more fructose than a real apple, yet can be consumed in a matter of minutes. On the other hand, who do you know that can comfortably eat four apples in two minutes?

This is important for two reasons: the liver has not evolved for the amount and speed by which we consume fructose today. Furthermore, we rarely consume fructose alone and this results in a cascade of biological events.

According to Gary Taubes, author of The Case Against Sugar, when the body has to metabolize both glucose and fructose (i.e. sucrose, in particular, high fructose corn syrup), the liver does not metabolize fructose efficiently.

When this happens, the body also becomes insulin resistant, meaning your cells begin to reject insulin, rendering you high in blood sugar and pre-diabetic.

To make matters worse, when your body cannot use glucose as fuel, it is stored as fat. Simply put, insulin resistance triggers obesity.

The final word

Just because apple juice tastes better than the real thing, your body pays a huge price for the indulgence. Choose real fruits, and avoid products with high fructose corn syrup.

As always, pushing for health.