Posted by Werner Mansfeld
on June 24, 2026
“Eat more fruit” is one of the most consistent pieces of nutrition advice that exists. For someone managing insulin resistance, it’s also incomplete advice, because fruit isn’t a single category that behaves the same way in the body. Two fruits with similar calorie counts can have very different effects on blood sugar and fat storage, depending on two separate factors: glycemic index and fructose content.
Two Different Measurements, Two Different Mechanisms
Glycemic index measures how quickly a food raises blood glucose levels. This matters because rapid glucose spikes drive a corresponding insulin spike, and repeated insulin spikes over time contribute to insulin resistance.
Fructose content measures something different: how much of a fruit’s sugar is specifically fructose, the sugar that’s metabolized through the liver via a pathway that can deplete cellular energy and generate uric acid, contributing to fat storage and insulin resistance through a separate mechanism than a glucose spike alone.
A fruit can score relatively low on one measure and higher on the other. This is why fruit can’t be sorted into a simple “good” and “bad” list using just one of these metrics.
A fruit can score low on one measure and high on the other — which is why “fruit is healthy” is too blunt a rule for insulin resistance.
Why Watermelon Is a Useful Example
Watermelon has a high glycemic index — around 76, similar to a bagel — meaning it raises blood glucose quickly. But its fructose content per serving is relatively low, at around 11 grams for a full slice. This means watermelon’s primary concern is glucose-spike related, not fructose-related.
Compare that to dried figs, which have a substantially higher fructose content per serving — around 23 grams in a single cup — making them a concern primarily through the fructose-and-uric-acid pathway, independent of any glucose spike.
Fruits Generally Lower in Both Categories
Berries tend to perform well on both measures. Strawberries, blackberries, and raspberries are relatively low in fructose per serving and have a more moderate glycemic profile compared to many other fruits. This is a meaningful part of why berries are frequently recommended as a “safer” fruit choice for people managing insulin resistance, while high-fructose options like dried fruit, mango, and watermelon in large quantities warrant more caution.
Why Dried Fruit Deserves Special Caution
Drying fruit concentrates its sugar content significantly. A cup of fresh grapes and a quarter cup of raisins come from roughly the same amount of fruit, but the raisins pack that fructose into a much smaller, easier-to-overconsume serving. The same applies to dried figs and dried apricots. This is one of the more common blind spots — dried fruit often gets treated as a “healthy snack” simply because it’s fruit, when its concentrated fructose content puts it closer to a more cautious category.
How to Use This Information
The practical takeaway isn’t to eliminate fruit. It’s to weight your choices toward lower-fructose, lower-glycemic options — berries in particular — while treating high-fructose fruits like mango, dried fruit, and large portions of watermelon as occasional choices rather than daily staples, especially if you’re actively working to lower an elevated IRS Score.
The bottom line
Reading both numbers, rather than relying on the general reputation of “fruit is healthy,” gives a much clearer picture of how a specific choice will actually affect your metabolism.
