Fruits, like most foods, contain carbohydrates that can raise your blood sugar. However, fruit also carries with it an abundance of healthy vitamins and minerals as well as fiber, which are part of a well-balanced diet. Understanding the benefits of fruit, as well as which fruits can drastically increase your blood sugar, is all part of ensuring blood-glucose control.
Sugars in Fruits
Most fruits contain the sugar fructose. Fructose is a type of carbohydrate called a monosaccharide that consists of a single sugar molecule, and one of the most common sugars found in nature. Most fruits also contain fiber, another carbohydrate or polysaccharide that's indigestible but has many health benefits. Fruits also contain pectin, which is a soluble fiber, and cellulose, an insoluble fiber.
Glycemic Index of Fruits
Since fruits contain carbohydrates, most fruits will increase your blood sugar. However, some can affect it more than others. A good way to determine a food's effect on your blood sugar is to know its glycemic index. The glycemic index is a rating given to food, indicating how quickly and drastically will increase your blood glucose. The scale ranges from zero to 100; the higher a food's score on the glycemic index, the higher and faster it will raise your blood sugar. If a food is between 0 and 55, it is considered a low-glycemic food. From 56 to 69, it's considered a moderate glycemic food, and from 70 to 100, it is a high-glycemic food. Glycemic load is another measure of a food's impact on blood sugar that takes into account its glycemic index relative to its content of all forms of carbohydrate, including fiber. For example, watermelon has a high-glycemic index but a low glycemic load because it raises blood sugar slowly. Fruits that have a moderately high glycemic effect include bananas, pineapple and raisins. Low-glycemic fruits are apples, oranges, mangoes and grapefruit.
Carbs and Fruit
According to the "Cecil Essentials of Medicine," diabetics should limit their intake of carbohydrates to 15 g per meal. This is equal to 1/2 cup of frozen fruit, 3/4 to 1 cup of melon or berries and 1/3 to 1/2 cup of fruit juice. Dried fruits, like raisins or cherries, can contain 25 g of carbs in just 2 tbsp.
Benefits of Fruit
The fiber content of fruit may be helpful in limiting the effect that fruit sugar has on your blood glucose. Eating fiber with a food lowers its glycemic effect. A high glycemic index means a spike in blood glucose, while a low-glycemic index food results in a moderate rise over a prolonged time. Fiber slows the digestion of foods and also blocks the absorption of sugars all at once. These combined factors result in a moderate rise in blood sugar over a significant amount of time. In addition, fruit offers an array of vitamins and minerals, so don't skip your intake of fruit just because you think it contains too much sugar.
- "Nutrition: Concepts and Controversies"; Frances Sizer and Eleanor Whitney; 2004
- American Diabetes Association; Fruits; 2011
- Mendosa.com; The Glycemic Index; David Mendosa; August 2002
- Harvard School of Public Health: Carbohydrates and the Glycemic Load
- Mendosa.com; Revised International Table of Glycemic Index (GI) and Glycemic Load (GL) Values — 2008; David Mendosa; December 2008