Coke adds stevia, but is it really any healthier?

What is stevia?

Stevia is a shrub native to South America and its leaves have been used for hundreds of years as a sweetener, often added to tea. It is about 200 times sweeter than natural sugar, has almost no kilojoules and does not raise blood sugar levels.

Is it healthier than sugar, or more natural than other sweeteners?

Dietitian Alan Barclay said stevia has benefits over sugar. It is a good option for people who want to reduce their kilojoule intake and avoid blood sugar spikes, he said, particularly people with diabetes or those at risk of developing the disease.

"A lot of people want to avoid artificial sweeteners so this provides what many regard as a natural alternative – but I must add that it is a highly refined extract," he said.

A major downside was a "liquorice-y taste" that usually led to it being blended with another sweetener such as sugar.

Will stevia reduce obesity?

Dr Barclay said stevia does not provide "a licence to drink Coke in large quantities,"  and claims that stevia is a key ingredient in the fight against obesity are overblown.

"It's not a panacea. This is definitely a better option but water is the best choice," he said.

Why are soft-drink manufacturers going down this path?

Obesity Policy Coalition spokeswoman Jane Martin said Coca-Cola Life was clearly an attempt to counter widespread concerns about sugary drinks, but she warned that diet cola still contains both sugar and caffeine.

"It's a positive step but we know Coca-Cola are heavily marketing their full sugar product, particularly to adolescent boys through Facebook," she said.

"Their recent 'Share a Coke' campaign was a massive success and it's a huge concern that they are using peer-to-peer marketing.

"We'd like to see them pull all their sugary drinks out of schools. With the introduction of $2 cans of Coke, often water is just as expensive."