Science Focus - the home of BBC Science Focus Magazine
Do apples really ripen faster if you put them next to bananas? © Getty Images

Is the sugar in fruit bad for us?

Subscribe to BBC Science Focus Magazine and get 6 issues for just £9.99

Surprisingly, a diet that’s rich in fresh fruit isn’t a high-fructose diet!

Asked by: Roger Britton, via email


The sugar in fruit is mostly fructose and glucose. Glucose is the primary food molecule, and can be used directly by the cells in your body. Fructose, however, must be converted into glucose before it can be used. This happens in the liver, but there is a limit as to how fast the liver can process fructose. When it is overloaded, it will instead convert the fructose into fat – so high-fructose diets tend to make you obese.

But surprisingly, a diet that’s rich in fresh fruit isn’t a high-fructose diet! That’s because fruits have a lot of fibre and water that slow down your digestion and make you feel full. In fact, research has found that apples and oranges are some of the most filling foods per calorie – higher than steak or eggs. So although a medium apple contains 19g of sugar, including 11g of fructose, you will feel less hungry afterwards than if you had the same amount of sugar from a fizzy drink (roughly half a can of Coke).

It is almost impossible to get too much sugar from fresh fruit, but this doesn’t apply to fruit juice or dried fruit. They are much easier to binge on.


Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun facts.


luis villazon
Luis VillazonQ&A expert

Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.


Sponsored content