Catherine Saxelby unveils the surprising truth about those fizzy diet drinks we love.
Do diet soft drinks make you fat?
Guzzle a 375ml can of regular soft drink, and you’ll consume about 10 teaspoons of sugar and 670kJ. If you switch to a can of diet or low-kJ soft drink instead, you’ll get no sugar (but sweeteners instead) and less than 5kJ. In theory, diet drinks make diet sense: Substitute regular soft drinks for diet ones and you’ll cut back on kilojoules. But does it backfire on you?
There’s research to suggest that dieters end up eating more as the brain doesn’t receive the usual hunger satiety signals and blood sugar feedback. By breaking the connection between a sweet sensation and high-kilojoule fare, sweeteners change the body’s ability to regulate intake.
This first came to light in a 2008 study from Purdue University in the US, where researchers reported that consuming an artificially sweetened food can lead to greater weight-gain than consuming the same food sweetened with sugar.
We also have our suspicions on artificial sweeteners such as aspartame, acesulfame K and truvia (the new, recently approved Stevia). While they’ve been cleared by food authorities, there have been links to associated health problems, such as brain cancer.
Are they less harmful to teeth enamel?
Diet drinks don’t contain the sugars that cause tooth decay, but they’re very acidic (try a pH of 2.4 to 3.1). Diet colas contain phosphoric acid (used to impart a ‘tang’, or sour flavour) while lemon and lime flavours use citric acid. Both these acids can cause dental erosion, where enamel is dissolved from tooth surfaces. So they can actually be just as harmful.
Do they really decalcify our bones?
Phosphoric acid has been linked to lower bone density in many studies, but not all researchers agree. It’s not just how much you drink, but how it affects your calcium-to-phosphorus ratio. Too much phosphorus with too little calcium can equal brittle bones, as soft drinks often replace milk in teen diets. Cola consumption has also been linked to kidney stones, and a 2007 study found that drinking two or more colas a day more than doubled the incidence of kidney disease. Oh dear!
Think of diet drinks not as a health choice, but as an aid to weight loss. They contain fewer kilojoules but still have the same drawbacks. Don’t drink them every day.