The Glycemic Index of Grapes

If you have diabetes or pre-diabetes, you can eat grapes so long as you stick to small servings that provide a limited number of carbohydrates. Grapes are a significant source of dietary carbohydrates, a lot of which are sugars so they have the potential to raise blood sugar levels fast. Fortunately, their glycemic index score is low, below 55. This means that the rise in blood sugar they generate is moderate and, most important, manageable. Provided, of course, intakes are limited to small servings. Naturally, not everyone is equally tolerant to grapes so effects on blood sugar may vary between diabetics which is something to think about when looking to introduce the fruit into your diet if you have diabetes.

Grapes glycemic index: 45-53 (low)

During digestion, carbohydrates get broken down into their simplest form, sugar, which is then absorbed into the bloodstream rising blood sugar levels (except fiber which doesn’t contribute to blood sugar). The glycemic index (GI) is a scale that estimates how fast the carbohydrates in a food raise blood sugar levels. Below 55 is a low GI. Between 56-69 is a moderate GI. Between 70-100 is a high GI. Foods with low GI’s raise blood sugar more slowly and steadily, allowing for better control. In part, this is owed to good amounts of dietary fiber which slows down sugar absorption into the bloodstream.

Grapes glycemic index and load

What is the glycemic index of grapes? The GI of grapes varies according to the type of fruit. Sweeter varieties have slightly higher GI scores, whilst less sweet varieties have slightly lower GI scores. But, on average, grapes glycemic index ranges from 45 to about 53. What this means is that the fruit generally has limited effects on blood sugar and can be eaten safely with diabetes, so long as intakes are reasonable and in accordance with the diabetic person’s individual nutritional requirements, tolerance to the fruit, degree of insulin resistance and level of physical activity. Eating too many grapes at once, too often can offset the benefits of a low glycemic index and cause spikes in blood sugar.

How many carbs in grapes?

Although grapes are not high-glycemic, they are significant sources of carbohydrates which makes it pivotal to enjoy them in moderation, especially with diabetes. According to variety, this is how many carbs there are in different amounts of the fruit:
1) Muscadine: 13.93 g of carbs per 100 g, 0.84 g per grape.
2) American slip-skin: 17.15 g of carbs per 100 g, 0.41 g per grape (weighing only 2.4 g each), 15.78 g per cup (92 g a cup).
3) Red/Green European variety: 18.1 g of carbs per 100 g, 8.87 g for 10 grapes (weighing 49 g), 27.33 g per cup (151 g a cup).

How much sugar in grapes?

Diabetic or not, we eat grapes because they are sweet and flavorful. But that sweetness is a result of a significant sugar content, hence the recommendation to enjoy them within reason, especially with diabetes. Here is how much sugar there is in grapes according to variety and amount:
1) Muscadine: almost no sugar to up to 25% sugar, depending on variety. So 100 g of the variety can have very little or up to 25 g of sugar, but you may not tell from the taste because they are also acidic.
2) American slip-skin: 16.25 g of sugar per 100 g, 0.39 per grape (weighing 2.4 g each), 14.95 g per cup (92 g a cup).
3) Red/Green European variety: 15.48 g of sugar per 100 g, 7.59 g for 10 grapes (weighing 49 g), 23.37 g per cup (151 g a cup).

Grapes glycemic index

Grapes glycemic load: 2-10 (low, for servings of up to 100 g)

The glycemic load (GL) is a scale that estimates how fast the carbohydrates in a serving of a food raise blood sugar levels. Between 0-10 is a low GL. Between 11-19 is a moderate GL. Over 20 is a high GL. The lower the GL, the lesser the effects on blood sugar. Typically, the smaller the serving of a food, the lesser carbohydrates it provides and the lower its GL score and effects on blood sugar.

The glycemic load of grapes is low, ranging from as little as 2 to as much as 10 for servings of up to 100 g. A serving size of 150 g and over is likely to have a moderate glycemic load for both American and European varieties.

10 muscadine grapes weighing 60 g have a glycemic load of only 4, while 100 g has a GL of 6-7.
10 American slip-skin grapes weighing 24 g have a glycemic load of only 2, while 100 g has a GL of 8-9.
1 cup of the same variety has a GL of 7-8 (92 g per cup).
10 red/green European variety grapes weighing 49 g have a glycemic load of 4-5, while 100 g has a GL of 8-10.
1 cup of the same variety has a GL of 12-14 (151 g per cup).

Considerations on grapes and diabetes

When you have diabetes or pre-diabetes, it’s important to keep track of how many carbs you are getting per day and, ideally, also per meal. At least loosely. Because carbohydrates become the sugar that rises in our bloodstream and fuels diabetes complications. Considering serving/portion size helps diabetics achieve just that: know how many carbs they are eating a day so they may be able to adjust their intake and achieve better blood sugar control, improved glucose tolerance and a better insulin response.

Grapes and diabetes make a good pair so long as portions are kept reasonable. The smaller the serving size, the fewer carbs you are getting and the lesser the impact on your blood sugar. This is perfectly illustrated above by the glycemic load values for different amounts of the fruit. An excessive intake invalidates the advantages of a low glycemic index and can make grapes a problematic food for diabetics.

Just as important, eat your grapes raw, with skin to make sure you get all the fiber from them. Dietary fiber has hypoglycemic effects, is satiating and favors appetite control, improves cholesterol and helps with weight management, all beneficial for diabetes management. Also, fruit are best eaten not before, but after a meal that provides some lean protein and a little fat to further help reduce their glycemic effects.

This post was updated on Thursday / August 13th, 2020 at 1:31 AM