Why Is Fruit Becoming Sweeter? The Answer to This Question Is More Complex Than You Think

In 2018, Melbourne Zoo decided to stop feeding some of its animals fruit because it was deemed too sweet for their own good. Red pandas and primates had been gaining weight, and some were even showing signs of tooth decay.

This decision highlights a bigger story about our relationship with fruit.

Too much sugar. Michael Lynch, the zoo’s head veterinarian, told the Sydney Morning Herald, “The issue is the cultivated fruits have been genetically modified to be much higher in sugar content than their natural, ancestral fruits.”

Initially, this idea may seem like a mere curiosity with little significance. However, the notion of “fruit being unhealthy because it has much higher sugar levels than it did in the good old days” has long been circulating online. But is it true?

A complex matter. Nutritional data from database FoodData Central show a sugar increase in some fruit. For instance, wild blueberries contain about 6.46% sugars, while commercially grown blueberries have around 9.96%.

This increase is significant, but the effect diminishes when you compare modern fruit to its ancestral varieties. A 2019 study reviewed British data since 1946 and found no notable differences in the sugar content of apples, white grapes, and strawberries over the decades.

It makes sense. Over the years, humans have “improved” fruit and vegetables to the point where they look nothing like their ancestors. Giovanni Stanchi was a 17th-century Italian still-life painter. Between 1645 and 1672, he painted a picture filled with peaches, pears, and watermelons. Those watermelons look nothing like the ones we eat today.

A painting by Giovanni Stanchi.

Watermelon is a plant native to Africa. By 1600, it had already become extremely popular in orchards across Europe. Stanchi’s still-life painting shows how watermelons have changed. By 1860, watermelons began to take on a more recognizable appearance.

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Beyond appearance. The taste of many fruit and vegetables has also changed, and not always for the better. Interestingly, Brussels sprouts are significantly less bitter now than they were 20 years ago.

When discussing the sugar content in fruit, it’s important to note that there’s a physical limit to how much sugar can be produced. According to some experts, sugar levels in fruit tend to converge within a similar range. This is because, like tomatoes, plants can’t produce more sugar without increasing in size or yielding less fruit, which isn’t commercially viable.

Other aspects to consider. According to Dowden’s research, “modern” super-sweet strawberries contain only 4.89% sugars, while kiwis have 8.99% and bananas have 12.23%. This provides an interesting insight. Botanist James Wong notes that plant breeders don’t simply increase sugar content. Instead, they tend to make fruit taste sweeter by reducing sour and bitter compounds.

This explains what was happening with the animals in Melbourne Zoo. The issue wasn’t the sugar levels in the fruit. Fructose packaged in fiber doesn’t raise blood sugar levels like refined sugars do. What happened was that the fruits were so delicious that pandas and primates began to neglect other food sources, leading to an unbalanced diet.

Not a human problem. Fruit becoming a larger part of our diet would be amazing news because that would indicate an overall improvement in society’s eating habits. Unfortunately, the reality is quite the opposite. The portion of processed food in people’s diets tripled between 1990 and 2010, increasing from 11% to 31.7%. As a result, the amount of added sugars in the population’s daily energy intake rose from 8.4% to 13%.

In the end, sweet fruit isn’t the biggest concern in our diets.

Images | Julia Zolotova | Christie’s

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