Reporter: Natalie Bonjolo

A teaspoon of sugar helps the medicine go down, but retired Perth GP Max Whisson reckons, fructose, an element of sugar comes with a bitter twist.

A life time of research has led Dr Whissen to believe it's the fructose in sugar, not fat, to blame for Australia's obesity problems.

"Some fats are bad for you for sure, not nearly as dangerous as the kind of fatness that develops by drinking soft drinks with fructose in" says Dr Whissen.

It's a theory gaining momentum across the country. Sydney author David Gillespie calls fructose sweet poison.

"It makes you an immediate candidate for type 2 diabetes, for heart disease and a range of cancers linked directly to the sugar".

While fructose is found in all sorts of foods, according to Dr Whissen, it's the sugar 'hit' you get from fizzy drinks doing the damage.

"The human body is simply not capable of dealing with the rapid intake of fructose such as you get from modern soft drinks".

As a corporate lawyer, Harnesh Singh drank several soft drinks a day…

"When I was working in the office I used to drink a lot of soft drinks and I realised I was putting on weight".

So this young entrepreneur decided to take on the big boys creating his own sparkling water with a secret ingredient.

He stumbled upon a sugar substitute called 'stevia' which is an intense sweeter made from a native South American plant and the beauty is, there are no calories…

Until recently, stevia could only be bought as a sugar substitute, but not used in commercially sold, food or drink.

"Any new food additive whether it's a preservative or an intense sweetener like stevia, will go through a rigorous safety assessment" says Lydia Buchtmann from Food Standards Australia and New Zealand. After the food watch dogs safety assessment, stevia was approved for use in Australia.

"It's 300 times sweeter than sugar, has fewer kilojoules in it and has a slight benefit of course if you're trying to manage your weight".

Compare the sugar in these popular drinks. One can of Coca Cola has10 teaspoons of sugar. A 600ml bottle of Vitamin Water contains 6 teaspoons and a bottle of the Perth made Blue Bear, just 1 teaspoon.

While Harnesh has a head start on the market he reckons it won't be long before other big brands follow his lead.

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