Diet soda is as bad for your health and waistline as regular soda, a report warns.

Billions of people drink artificially-sweetened beverages to avoid the calories of sugar.

But according to a five-year study by Purdue University, diet soda is just as likely to lead to obesity.

And even diet soda drinkers who do not put on weight have a significantly increased risk of developing diabetes or heart disease, or of having a stroke.

Researchers admitted even they were surprised by the results.

According to a five-year study by Purdue University, diet soda is just as likely to lead to obesity

'Honestly, I thought that diet soda would be marginally better compared to regular soda in terms of health,' said lead author Professor Susan Swithers, an expert in neuroscience and psychological sciences.

'But in reality, it has a counterintuitive effect.'

There is no denying fake sugar contains fewer calories.

However, their study showed that the false promise of real calories confuses the body.

When diet soda drinkers do eat real sugar, their body does not know how to respond.

After enough soda-drinking, sweet-tasting foods do not trigger the natural release of a hormone to regulate blood sugar.

It means the blood sugar will then plummet, triggering hunger and cravings for sweet food.

Beyond that, diet soda also wears down the brain's 'reward center' by constantly triggering a rush of satisfaction.

Like with repeated drug use, the brain eventually gets used to this level of stimulation - causing you to eat more and more in a bid to reach that level of satisfaction.

The American Beverage Association has hit back at the report, questioning its validity since it was published as an opinion piece in the journal Cell.

'Low-calorie sweeteners are some of the most studied and reviewed ingredients in the food supply today,' the association said in a statement.