The Glycemic Load of Fruit

A healthy diet should almost always include some fruit, and this is particularly true if you’re suffering from adrenal fatigue. The difficulty arises in choosing the best and most nutritious fruits to eat. Most nutritionists will recommend sticking to the fruits with lower sugar content where possible, and this makes a lot of sense. But how do we measure the sugars in a particular fruit, and which fruits have the lowest amounts?

First of all, it’s important to understand how we really measure the sugars in fruit. We don’t actually take a piece of fruit, examine it in the lab, and quantify the grams of sugar in each portion. What actually happens is that we measure the effect that that fruit has on our blood sugar levels. There are two ways to represent this – Glycemic Index (GI) and Glycemic Load (GL). First I’ll explain how these measures work, and at the end of article I have included two tables with the numbers for various fruits.


The Glycemic Index of a food is a numerical unit describing how far eating a food will raise one’s blood sugar level; effectively, it represents how ‘sugary’ the food is. The Glycemic Index uses a scale from 0 to 100, where 100 is pure glucose. A food which has a high GI will cause a large increase in blood sugar, while a food with a lower GI will not have much impact at all. As a rough basis, mid-50s to mid-60s in a food’s GI is considered average, while 70 and above is considered high. Foods with a GI of less than 55 are considered to have a low glycemic index, and thus will have smaller impact on blood sugar levels.

The main problem with the Glycemic Index is that it does not factor in typical portion sizes. In fact, it standardizes each food to include 50 grams of carbohydrates. This leads to some peculiar distortions. For example, to obtain 50 grams of carbohydrates you would need either 2.8 ounces of a Snickers bar or 35 ounces of pumpkin. It hardly seems fair to compare the two when these portion sizes are so unrealistic!

In 1997, researchers at Harvard University introduced the concept of Glycemic Load with the aim of solving this problem. The Glycemic Load seeks to balance the Glycemic Index by accounting for serving size. Let’s take a watermelon as an example. It has a high GI, as the carbohydrate will increase blood sugar levels rapidly, but it contains a relatively small amount of the carbohydrate, meaning that it has a low glycemic load.

A food’s Glycemic Load is calculated directly from its Glycemic Index. We simply take the food’s Glycemic Index, divide it by 100, and multiply it by the grams of carbohydrate (excluding fiber) in a typical serving size. A GL of above 20 is considered high, the 11-19 range is considered average, and below 11 is low.

Let’s look again at watermelon. It has a Glycemic Index of 72, which is relatively high. However, a typical serving size only has 5 grams of carbohydrate. This means we can calculate the Glycemic Load like this: 72/100*5 = 3.6. Although the Glycemic Index is high, the Glycemic Load is relatively low. Which one is more useful to us? The Glycemic Load.

Watermelons are an unusual case, insofar as they have a high Glycemic Index (above 70 is considered high), yet have a low Glycemic Load (below 11 is low). This is not common, as most foods with a high GI will have a correspondingly high GL.


Here are two tables containing the Glycemic Load of various fruits, taken from the American Journal of Clinical Nutrition in 2012 (see the full version here). Remember that a GL of more than 20 is considered high, a GL of 11-19 is considered average, and a GL of below 11 is considered low. I have created a table showing the fruits in alphabetical order, and one showing them ordered by Glycemic Load.



FruitGlycemic LoadFruitGlycemic Load

Bear in mind that a high GI and GL does not necessarily mean that fruits are unhealthy and should be avoided. In fact, fruits are some of the healthiest carbohydrates a person can consume. They contain lots of antioxidants and vitamins, and the sugar they contain is in the form of fructose – much better than glucose. You may have read about high fructose corn syrup, which has emerged in a shocking number of everyday processed foods, but don’t worry: the fructose in fruit is natural and desirable, rather than being a cheap, unhealthy way to sweeten products.
Are You Suffering From Adrenal Fatigue?

Do you find yourself constantly fatigued, and struggling to get out of bed in the mornings? Do you feel unable to cope with stressful situations? If so, you might be suffering from Adrenal Fatigue Syndrome.

2 thoughts on “The Glycemic Load of Fruit”

  1. I believe the glycemic load for an entire fruit like an apple or kiwi is based on eating the entire serving. with watermelon, would this be like a 3 oz serving or a certain size slice because you can’t eat the whole watermelon?


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