In recent years, sugar has become the latest bogeyman of the healthy eating movement. There’s an increasing amount of evidence that, when consumed to excess, sugar can have a negative effect on your health, not to mention athletic performance.

What about the (so-called) health foods that are marketed as containing “natural fruit sugars,” though? Are “natural” sugars really better for you than “unnatural” sugars? (And what’s an “unnatural” sugar anyway?)  How do the sugars in fruit juice compare to the sugars in soda?

Sugar chemistry

Sugar molecules come in different forms. First of all, we have simple sugars – two of the most common being glucose and fructose. These simple sugar molecules can stick together to form more complex sugars. Table sugar (sucrose), for example, is made up of one molecule of glucose stuck to one molecule of fructose. It’s also possible for long chains of these simple sugar molecules to stick together, such as when starch is formed from lots of individual glucose molecules.

So, how does the sugar we find in fruit differ from refined sugar that gets added to cakes or drinks, then?

The simple answer is: it doesn’t. Fruit contains the exact same sugar molecules that you’d find in your can of Coke or Krispy Kreme donut, mostly a combination of glucose and fructose. The ratio of these two sugar molecules can vary from one food to another, and this is sometimes a focus of groups claiming that one particular kind of sugar is worse for you than another. For example, high fructose corn syrup usually contains between 42 and 55 percent fructose (the rest being glucose), and this is sometimes singled out by healthy eating campaigners as being particularly bad.

It’s true that glucose and fructose are metabolized in different ways by the body. Glucose is a form of sugar that most of the cells in our body use directly. Fructose, on the other hand, has to be processed by the liver first before we can use it for energy. This extra step means that it is absorbed more slowly by the body and results in a smaller insulin response; but on the other hand, it is also more likely to be converted to fat and can lead to higher levels of “bad” cholesterol. It can be argued that when consumed in very large quantities, high levels of fructose may have some more damaging effects than the same amount of glucose, but other researchers have pointed out that we don’t have strong evidence that one kind of sugar is significantly worse than the other overall.

So, you’re saying that fruit is bad for me?

Woah there, wait up. That’s not what we’re saying. The difference between eating an apple and drinking a glass of apple juice is to do with what else you’re consuming, apart from the sugar. The sugar in an apple comes packaged along with a whole lot of fiber (and some vitamins and other good stuff too, but that’s less of a concern here). If you eat the fruit, you’ll feel more full, and be less likely to overindulge, plus, the sugar will be released more slowly into your bloodstream. The sugar in a standard can of Coke may very well come directly from sugar cane (as the manufacturers like to point out), but to get the same amount of sugar (35g), you’d have to eat some 350g of raw sugar cane. If you actually did that, we’re prepared to bet that you might not feel like eating much else for a while. Although in theory you can overeat fruit, just as you can with any food, in practice, most people would find that quite hard work. Overindulging on Skittles, donuts or soda (while still leaving room for ice cream) is much easier.
Fruit juice, on the other hand, is a whole different barrel of apples. Stripped of the fiber that naturally accompanies the sugar, what we’re left with is essentially a fructose and glucose solution that’s not all that different from a glass of soda. The ratio of fructose to glucose may well be higher than in that can of Coke, but the real problem is the total amount. A small 250ml (8.45 ounce) glass of apple juice contains about as much sugar as a Cadbury’s crème egg. Fruit juice is not a healthy option; it’s dessert!

The verdict: FALSE.

“Natural” fruit sugars are no different from refined sugar—they’re chemically the same, and refined sugar comes from plants just the same way that the sugar in your apple juice does. Processed food products that proudly claim to contain “healthy natural fruit sugars” are no different from those containing any other kind of sugar (and we’re still not sure what an “unnatural” sugar is!). The only thing that makes a difference is what you’re consuming with the sugar. If you’re eating the whole fruit, then you’re getting a handy dose of fiber with your sugar, and we know that eating fiber and sugar together changes the effect that the sugar has on both your metabolism and your appetite.

If you’re a competitive bodybuilder or weight class athlete, and you’re trying to get rid of those last few percentage points of bodyfat, then cutting down on your fruit intake may make sense. For everyone else, though, it’s one of the last things you should be worrying about. Just make sure you leave the sugar in the fruit!