20 April 2011

Is sugar a baddie?

Sugar makes you fat, saps your energy, and shouldn't form part of a healthy diet. A dietician debunks these, and other common myths, about sugar intake.


Sugar is one of those villains in nutrition that is easily positioned as a bad guy. It provides nothing except energy, so has no redeeming features in the eyes of the diet police.

To top it all, many people enjoy its sweet taste, and we have a prudish notion that if it tastes good, it must be bad for us. Fail to fight your sweet tooth and you will fail to achieve good nutrition goals. Sound familiar?

Sugar has received bad press for decades, but this has a positive spin off. The controversy has sparked tens of thousands of research studies to determine the impact of this ubiquitous food on health.

The outcome of these research studies have periodically been summarised in major reports to paint a broad picture regarding the use of sugar in the diet. All these reports agree that, apart from its contribution to dental caries, sugar can be enjoyed as part of a balanced diet.

Different types of sugar

Sugar is formed in green plants in the presence of sun and water, through photosynthesis. This process produces the sugar in vegetables, fruits and sugar cane. The sugars from these sources are the same: they have a mix of the single-unit sugars glucose and fructose, and the double-unit sugar sucrose (which is made up of glucose and fructose).

Fructose is often called fruit sugar, and many people think that it is only found in fruit, and is the only sugar in fruit. This is not true. For example, 100g of mango has 0,8g of glucose, 3,4g of fructose, and 10,8g of sucrose. This sucrose is identical to the sucrose taken from a packet of table sugar and added to your tea. These sugars are digested in the same way, irrespective of source.

Sugar and weight loss

Should you avoid sugar if you want to lose weight? Not necessarily. No single nutrient is responsible for weight gain, so no single nutrient has to be excluded to achieve weight loss and weight maintenance.

The energy value of a reducing diet must be less than your daily energy needs, but balance should be maintained. Including sugar in mixed meals can help to maintain the good taste of foods, and so help to make it easier to stick to the reducing diet. In many cases, it has been shown that people who eat sugar eat less fat, helping to keep their diets heart-friendly.

Decades ago, it was assumed that simple sugars would be absorbed quickly by the blood stream, causing a peak in blood sugar, followed by a drop.

This was proven to be wrong when the glycaemic index (GI) was described in the early 1980s. Sugar was found to have an intermediate GI, similar to that of many starchy foods such as bread and rice.

Ironically, 25 years later, the misconception about sugar causing a peak and then a drop in blood sugar still flourishes.

Sugar and your teeth

Tooth decay (dental caries) is promoted by incorrect consumption of sugar and other foods that can be fermented by the bacteria in the mouth.

Caries is more likely to develop when a person doesn't brush their teeth regularly with fluoride toothpaste and doesn't floss to remove residues from between teeth.

Another contributing factor is when these foods are in the mouth for extended periods of time, e.g. sucking sweets or sipping a cold drink slowly.

A very severe type of caries can occur in young children who are given a bottle that contains a sweetened drink, especially if they fall asleep sucking the bottle. This can occur if pure fruit juice, cold drinks or sweetened tea is given. This form of tooth decay can be painful, unsightly and can impact on the development of the child’s primary teeth and on speech.

How much sugar is OK?

The quantity of sugar that any person can eat will depend on the persons’ total energy needs. An active young person will eat more than an older person who is sedentary.

Sugar, and sugar-rich foods, should never be eaten instead of good mixed meals, but can be used to make the meals taste good, or to provide a sweet treat after the meal.

Written by Carol Browne, registered dietician

- (Updated by Health24, April 2011)

Read more:

The aspartame controversy
Sucralose: sweet guilt-free seduction

The fructose controversy


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