The two researchers who uncovered the dangers behind high-fructose corn syrup in soft drinks in 2004, Barry Popkin and George Bray, recently spoke to the Guardian about why smoothies and fruit juices are deceptively unhealthy and could be the "new danger."

High amounts of sugar found in smoothies can be just as fattening as a "large Coke," the researchers claim, noting that companies like Coca Cola and Pepsi have been buying rival smoothie and fruit juice firms across the globe.

"Smoothies and fruit juices are the new danger," Popkin told the Guardian. "It's kind of the next step in the evolution of the battle. And it's a really big part of it because in every country they've been replacing soft drinks with fruit juice and smoothies as the new healthy beverage."

Popkin, a professor at the department of nutrition at the University of North Carolina, explained that Pepsi "had marketed a 250ml portion of its smoothies as providing two of the nation's five portions of fruit and vegetables a day," according to the Daily Mail.

"So pulped up smoothies do nothing good for us, but do give us the same amount of sugar as four to six oranges or a large coke. It is deceiving," Popkin said.

Last week, the British Medical Association released a report stating that those who drank fruit juices were at a higher risk of developing type two diabetes than those who ate whole fruits.

"Obesity is a serious and complex problem requiring concerted action by a wide range of organizations as well as by people themselves,"  the British Soft Drinks Association said in a recent statement on how in the last 10 years, the consumption soft drinks containing sugar has fallen by nine percent. "Soft drinks companies recognize the role they have to play."

The researchers note that vegetable juice can be a healthy alternative to sugary juices and smoothies.