Sugar Poison

Excess sugar is not healthy and unfortunately, there is very little on the supermarket shelves that does not have sugar in some form.

All carbohydrates are digested to glucose. Except for the very complex ones like cellulose (a fibrous complex carbohydrate that is not digestible by humans).

So all carbs either end up as glucose in your system, or are passed right through to the other end.

Sugar is essential to life. The blood glucose levels are kept optimal by the body. Normally, the blood sugars will rise after you eat and then slowly decline. People who are fasting will have a lower blood sugar since they're not putting any sugar into their diet during fasting.

And by sugar, I mean glucose. The molecular structure of glucose is a chain of six carbon atoms with 12 hydrogen and 6 oxygen atoms bound to it.

It's called a monosaccharide, because it's a simple sugar. Simple sugars cannot be broken down to make other sugars. Examples of simple sugars are glucose, fructose and galactose.

There are complex sugars, polysaccharides, which can be broken down to make simple sugars. For example, table sugar, or sucrose, is made of a fructose molecule bonded to a glucose molecule. During the metabolism of sucrose by the body, it is broken into glucose and fructose.

At the end of the metabolism of carbohydrates, or complex sugars, we get glucose. Glucose is sent to the cells in the blood where it is used for the various processes that need energy.

When glucose is introduced into the blood, the blood sugar level rises. This is normal when you eat carbohydrates, however, if the blood sugar rises too high, the body must remove it from the blood. 

That's where insulin comes in. Insulin's job is to take sugar (glucose) from the blood and allow it to cross into the cells where it can be used. It also takes excess sugar and stores it as glycogen in the muscle tissues. Once the glycogen stores are full, it then takes the excess and allows it to be stored in fat cells.

When sugar is present, you cannot burn fat. Insulin stops the liver from making glucose since there is enough sugar present in the blood.

While it's often touted that glucose is the preferred energy source for human beings, it's nutritionally light. Also, note that when glucose is present, the body cannot burn any fat. In fact the body only burns fat when there is not enough glucose in the blood. The liver makes glucose by a metabolic process known as gluconeogenesis (gluco=glucose, neo=new, genesis=make).

EXCESS SUGAR IS THE CULPRIT

In our modern lifestyle, we eat when we are hungry. For the most part, we thrive on food rich in sugar.

Ancient humans also ate when they were hungry, but they did not always have food readily available. The normal practice was therefore to engorge when food was available, and then to fast, when food was not available. During those necessary fasting periods, the body consumed the glycogen and the fat that had been stored in the muscles and the fat cells.

However, modern humans eat when they are hungry and do not allow the normal fasting process that would then allow for the metabolism of glycogen and fat to take place. This is mostly because food is available. In addition, most of the food that is available is carbohydrate rich.

Therefore sugar is not the enemy. Excess sugar, by continual consumption to ease hunger, is the culprit?

What should we do? Should we not eat when we are hungry?

This is the dilemma we face as modern humans with sugar-rich food readily available. The normal tendency is to ease the hunger (an uncomfortable state) by eating to satiety.

Instead, what we need to learn to do is ignore the hunger and prolong it to allow the body to move through a fasting cycle. This fasting cycle is necessary to lower blood sugar and trigger the liver into gluconeogeness and the consumption of stored energy.

THE STORY ABOUT FRUCTOSE

Fructose is poorly absorbed by the gastrointestinal tract. It's the liver that has to deal with it When the liver digests fructose, we get glucose, lactate and fatty acids. The small intestine can also digest fructose but most of the work is done by the liver.

Half of the common sugar molecule, sucrose, is fructose while the other half is glucose. So when you have table sugar in your coffee, the glucose part will be transported directly into the blood and then insulin will help it get into the cells, while the fructose part needs to travel a little further before it is processed.

Mostly because of this, fructose digestion favours conversion to fat, either glycogen stored in the muscles or into fat cells for storage, and mostly around the liver. This is why you're more likely to get fatter on high fructose diets than glucose, or even fat itself.

SUMMARY

So, to cut a very long, and complex, story short, here's what we know.

• Glucose is essential, but you don't have to eat it - the body knows how to make it.
• Limit carbs - they are nothing but glucose in another form.
• Try to fast, don't eat when you get hungry, let your body get used to hunger.
• Avoid packaged foods with fructose - especially fructose corn syrup.