Diet Coke sales have dropped dramatically, according to Coca-Cola’s latest results.

The company said that global sales of Diet Coke fell 7 per cent on the same quarter last year, continuing a decline that started in 2008.

Here are two possible reasons:

1. Analysts have attributed its decline to rising consumer awareness of the obesity risks of sugary drinks.

Euromonitor noted in 2013 that "as consumer awareness of the risks of a high sugar diet has grown, the sugar content of regular Coca-Cola could hinder the company as the consumer agenda increasingly switches to looking for healthier food and drink options".

Sandy Douglas, president of Coca-Cola North America, said that declining Diet Coke sales are linked to the trend for fresh food and drink.

"It's a good dietary change, actually, for the country. But the impact on categories, and particularly categories that are appealing to diet-oriented positions, has been pretty negative," he said, according to AP.

The trend for fresher food has already inspired PepsiCo to take artificial sweeteners out of Diet Pepsi. Last year it launched Pepsi True, which has 30 per cent fewer calories than normal Pepsi and is sweetened using a naturally occurring sweetener called stevia.

In April, it replaced aspartame, a controversial chemical that has been linked with brain tumours, with sucralose, or Splenda as it is more commonly known. US sales of Diet Pepsi were down 5.2 per cent last year, according to data from Beverage Today.

Consumers have gone from dodging sugar by buying diet drinks, to switching back to sugar because of concerns about sugar substitutes.

2. The number of different soft drinks available to customers may have resulted in cannibalisation of soft drinks within the same brand.

Euromonitor said that between 2007 and 2012, sales of Diet Coke declined in France and the US, but sales of Coke Zero increased.

Which coke should you buy?

One can of normal Coca-Cola contains 35g of sugars, or 39 per cent of your recommended daily allowance.

Both Diet Coke and and Coke Zero contain no sugars at all, but they contain artificial sweeteners such as aspartame.