Dentists have spent years begging us to stop eating sweets and drinking wine.
But there may be something worse than enjoying the occasional bag of Haribo - and it's something all of us do.
So, what is it?
Sipping your drink, according to Dr Dante Devoti, a New York City-based dentist.
He said: 'Tooth enamel is the hardest mineralized substance in your body.
'But prolonged exposure to acid - especially acidic liquids - can cause teeth to demineralize, erode.'
This makes them more susceptible to cavities, he said.
Dr Devoti, who works at Columbia University's College of Dental Medicine, added: 'Drinking one cup of coffee, tea, juice, or other drink in a single sitting is better for your teeth than sipping one cup throughout the entire day.'
Saliva slowly neutralises the acidity.
But it can take up to an hour to neutralise pH levels in your mouth to the 'protective range', Dr Devoti said.
When you regularly sip the same drink, saliva doesn't have time to raise the pH (low numbers indicate more acidic). Seven is neutral.
Similar logic on sipping would apply to alcohol and sports drinks.
But fizzy carbonated drinks are the worst, Dr Devoti said.
'Drinking soda is essentially a sugary acid bath for the teeth,' he added in a piece written on his university's website.
Not only does the sugar lower the pH level, but it is also a food source for harmful bacteria which 'creates a cycle of destruction to your teeth'.
Bacteria consume sugars and convert them into acid which reduces acidity levels further.
Dr Devoti, an assistant professor of dental medicine, said: 'When there's repeated, long exposures, almost all food and drink can be considered harmful to teeth.
'Good oral habits go beyond brushing and flossing to recognising how eating and drinking habits, such as frequently snacking or sipping on beverages throughout the day, can be equally impactful on the health of our teeth.'
In the UK, around 50 per cent of four to 18-year-olds have some tooth erosion and around three quarters of all Brits do not have a full set of natural teeth.
In the US, 46 per cent of young adults show signs of tooth erosion.
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