A medium green apple (Granny Smith) contains roughly 19 grams of sugar. Per 100 grams of fruit, that works out to about 10.6 grams, making Granny Smith one of the lowest-sugar apple varieties you can buy.
Sugar Content by Apple Size
A medium Granny Smith apple weighs about 182 grams and delivers approximately 19 grams of total sugar along with 25 grams of carbohydrates and 95 calories. A small apple (around 150 grams) will have closer to 16 grams of sugar, while a large one can push past 22 grams. The simplest way to estimate: every 100 grams of Granny Smith flesh contains 10.6 grams of sugar.
How Green Apples Compare to Other Varieties
Granny Smith apples consistently have less sugar than red and yellow varieties. Here’s how they stack up per 100 grams:
- Granny Smith: 10.6 g sugar, 14.1 g total carbs
- Red Delicious: 12.2 g sugar, 14.8 g total carbs
- Honeycrisp: 12.4 g sugar, 14.7 g total carbs
- Fuji: 13.3 g sugar, 15.6 g total carbs
That gap matters more than it looks. A medium Fuji apple can contain 4 to 5 more grams of sugar than a same-sized Granny Smith, roughly the equivalent of an extra teaspoon of table sugar.
What Types of Sugar Are in a Green Apple
The sugar in apples isn’t just one thing. It’s a mix of three types: fructose (fruit sugar), sucrose (the same compound as table sugar), and glucose. In most apple varieties, fructose dominates, typically making up about half the total sugar content. Glucose contributes the smallest share, usually under 2 grams per 100 grams of fruit.
Tart varieties like Granny Smith tend to sit at the lower end for fructose compared to sweeter cultivars like Golden Delicious, which can reach over 8 grams of fructose per 100 grams. The tartness you taste in a green apple comes partly from its higher acid content relative to its sugar, not just from having less sugar overall.
Why Ripeness Changes the Sugar Count
A green apple picked early and one left on the tree longer won’t have the same sugar content. As apples mature, starch stored in the flesh gradually converts into sugar. At the same time, acidity decreases. This is why an underripe Granny Smith tastes sharply sour while a fully ripe one has a noticeably sweeter, mellower flavor, even though the variety is known for tartness. If you buy green apples that have been stored for a while, they’ll likely be slightly sweeter than ones fresh off the tree.
Green Apples and Blood Sugar
Despite containing natural sugar, green apples have a low glycemic index, typically around 38. Foods under 55 on the glycemic index scale are considered “low,” meaning they cause a slower, more gradual rise in blood sugar rather than a sharp spike. One reason for this: a medium Granny Smith delivers about 4.4 grams of dietary fiber, which slows down how quickly sugar enters your bloodstream.
That combination of lower sugar content, higher acidity, and solid fiber makes Granny Smith apples a particularly good choice if you’re watching your blood sugar. The fiber also means that the 19 grams of sugar in a whole apple behaves very differently in your body than 19 grams of sugar from candy or juice, where there’s no fiber to slow absorption.