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Sugary drinks are high in kilojoules (energy) and low in nutritional value. We know that regularly drinking sugary drinks can lead to weight gain and obesity, increasing risk of serious health problems including dental decay, type 2 diabetes, heart disease and some cancers.

But what about the alternatives? ‘Diet’ or ‘sugar-free’ drinks, taste sweet but without the added kilojoules. Are they healthier? Let’s look into it.

First, why are sugary drinks bad for you?

The average 600ml bottle of soft drink contains 16 teaspoons of sugar and about 1,000 unnecessary or ‘empty’ kilojoules. This means that they exceed the World Health Organization’s recommendations for sugar (which is around 12 teaspoons per day for the average adult), they offer little to no nutritional value, plus they’re acidic which is bad for our teeth.

We know that regular consumption of sugary drinks can lead to weight gain, as people usually don’t account for the extra kilojoules coming from sugary drinks.

Sneakily, drink companies have found a way to overcome this concern. They can use artificial sweeteners to sweeten beverages instead of sugar, which contain little to no kilojoules. But are these ‘diet’ drinks any better for us than the sugary drinks they impersonate?

Are sugar-free drinks actually healthier?

There are many suspicions about the healthiness of artificial sweeteners, with some critics suggesting they may cause more harm than good and are no better than their sugary counterparts. So, what does the evidence say?

Artificial sweeteners are synthetic chemical compounds which provide very few kilojoules and taste intensely sweeter than sugar. This means that when used as a sugar replacement, much less is required to achieve the desired level of sweetness.

There are several types of artificial sweeteners including aspartame, sucralose, cyclamate and saccharin, all of which are approved and regulated by the Food Standards of Australia and New Zealand (FSANZ).

There have been rumours that some artificial sweeteners can cause cancer. There is no evidence to suggest that artificial sweeteners found in ‘diet’ drinks cause cancer. In Australia, FSANZ sets acceptable levels for all types of additives including artificial sweeteners, which are allowed to be used in drinks. These levels are regularly reviewed and adjusted by FSANZ according to the evidence to ensure our safety. Read more about artificial sweeteners and cancer here.

Are sugar-free drinks good for weight loss?

Due to their low kilojoule content, artificially sweetened beverages like ‘diet’ soft drinks are often chosen to help maintain or lose weight. However, the evidence for artificial sweeteners and their effect on weight is inconsistent.

Some studies have shown that people who substitute sugar sweetened beverages with ‘diet’ drinks, lose weight. Other studies have found ‘diet’ drinks are associated with overeating and weight gain. The reason for this is unclear but thought to be as a result of either artificial sweeteners not leaving you feeling full, or perhaps a sense of freedom to eat more because you’ve had a low-calorie drink.

Is it better to drink sugar-free drinks or drinks with sugar?

Given the mixed evidence on the effectiveness of artificial sweeteners for weight management, we do not recommend swapping sugary drinks for ‘diet’ drinks when trying to achieve or maintain a healthy weight.

Although they do not contain the same level of kilojoules as their sugar-sweetened counterparts, they can cause tooth erosion.

We recommend drinking water or low-fat milk. Water is the best option for hydration and low-fat milk provides important nutrients such as calcium and protein, which supports healthy bones and teeth.

At the end of the day, water is naturally sugar free….since forever!

Cancer Council SA’s current Rethink Sugary Drinks campaign aims to educate South Australians on the sugar content of some of our favourite drinks and encourages them to choose water instead. For more information visit


  1. Food Standards of Australia and New Zealand (FSANZ) 2021. Intense Sweeteners. Available at:
  2. Hector et al 2009. Soft drinks, weight status and health: a review. A NSW Centre for Public Health Nutrition (now known as Cluster of Public Health Nutrition, Prevention Research Collaboration, University of Sydney) project for NSW Health, 2009.
  3. Richard, A and Smith, G 2020. Artificial sweeteners vs sugar. CHOICE. Available at:
  4. World Health Organization 2015. Guideline: sugars intake for adults and children. Available at: