Health advice around sugar can feel contradictory. People are told to cut back on sugar and sweets, yet encouraged to eat plenty of sweet fruit. Because fruit contains natural sugar, many wonder whether that sugar is really any different from the sugar found in sweets, cold drinks or processed food. Heart surgeon Dr. Jeremy London addressed this confusion in a post on Instagram.
According to Dr. London, the answer is both yes and no. Sugar is chemically identical wherever it comes from, but how the body digests it depends entirely on what else is being consumed alongside it.
The sugar molecules are the same, so where's the difference?
Dr. London explains that the sweetness in fruit and in sweets both comes from essentially the same sugar molecules. If those molecules were isolated and eaten completely on their own, the body would process them in the same way. The real difference, he says, lies in everything else that surrounds those sugar molecules. He gave the example that an apple contains sugar and a glazed donut also contains sugar, chemically the sugar itself is identical in both. But the way the body digests the two is completely different. Sugar is present in both, yet what accompanies that sugar makes a massive difference to what happens inside the body.
Why whole fruit affects the body more slowly
Dr. London points out that whole fruit does contain natural sugar, but it also comes packaged with fiber and water. That fiber and water slow down digestion and blunt the sharp blood sugar spike that usually follows eating the same amount of sugar on its own. Fruit is also rich in polyphenols and micronutrients, giving it nutritional benefits that processed sugar simply does not offer. An apple, for instance, contains fiber, water, polyphenols and antioxidants together. All of these slow down digestion, which directly affects how the body processes the sugar it contains. That in turn shapes the fruit's glycemic index as well as the body's overall sugar metabolism.
Why juice and dried fruit don't offer the same benefits
Dr. London was clear that these benefits apply specifically to whole fruit. When he talks about whole fruit, he means literally whole fruit, because juicing or drying fruit strips away much of this nutritional value. Fruit juice loses almost all of its fiber in the process, which leaves it behaving much like a sweet drink. Dried fruit, on the other hand, holds onto its fiber but loses most of its water, which concentrates the sugar and makes it far easier to eat a much larger amount of sugar in a short span of time.
Why fruit remains the smarter source of sugar
Dr. London notes that whole fruit is far more filling for its calorie count than sugary drinks or processed snacks. That's a key reason fruit is considered the best source of natural sugar. Eating fruit also delivers essential nutrients to the body that processed sugar can never provide. Taken together, Dr. London's post makes the point that it isn't enough to just look at how much sugar something contains, what matters just as much is what else is arriving in the body alongside that sugar.
