How can fruit affect blood sugar, and are there certain types of fruit that are better for people with diabetes?
It’s important for people with diabetes to be careful about what they eat, especially when it comes to sweet foods. That’s what can make eating fruit so tricky.
Even though fruits are natural and full of healthy vitamins and minerals, many of them also pack in fructose (the sugar found in fruit), a carbohydrate that can raise your blood glucose levels. The good news is that fruits are fine to eat so long as you monitor the types and amounts. (Where this doesn’t apply is allergies. If you are allergic to a certain fruit, you’ll want to stay away from that – for obvious reasons!)
How does fruit affect blood sugar?
The main sugar in fruit, called fructose, is quickly taken up by the liver, converted to glucose, and released into the bloodstream. So, fruit can cause glucose levels to rise. However, fruits also contain fiber, a nutrient that can slow carbohydrate digestion and help manage blood sugar levels. Different fruits contain varied amounts of fructose, glucose, and fiber, meaning that the type of fruit you eat will determine how it affects your blood sugar.
The type of sugar found in fruit is different from the simple sugar that is added to processed foods, like soda or ice cream. Because the carbohydrates in fruit are accompanied by fiber, vitamins, and minerals, eating fruit in moderation will generally affect blood sugar levels differently – and more slowly – than eating candy.
Is it important for people with type 1 and type 2 diabetes to be careful about how much fruit you eat?
Yes. For all people, and for all people with diabetes, fruit can affect your blood sugar level. That doesn’t mean that you shouldn’t eat fruit at all – fruit still includes important nutrients that your body needs, some of which can lower your risk of heart disease, type 2 diabetes, and other chronic conditions.
How much fruit should someone with diabetes eat?
The US Dietary Guidelines recommend that all adults eat about two cups of fruit per day, where one piece of fruit is about the size of a one-cup serving. People with diabetes should still eat fruit, but should be more mindful of fruit intake, paying attention to the type and amount of fruit that you eat. Pairing fruit with foods that also have protein and fat (like eating an apple with peanut butter or eating berries with plain yogurt) can help prevent a blood sugar spike.
How to manage your fruit intake
How can you determine how much fruit you should eat?
It’s important to take a fruit’s carbs into consideration when you are planning meals, dosing insulin, or calculating carbohydrate intake. One serving of fruit has 15 grams of carbs; however, this is where it can get tricky – one serving of fruit looks different depending on what you are eating. Here are some examples of single servings of fruit (all contain about 15 grams of carbohydrate):
- Half an apple
- Half a banana
- One cup of blackberries
- One big cup of strawberries
- One cup of watermelon or cantaloupe
- A handful of grapes
- One big tablespoon of dried fruit
If you eat a serving a fruit, be sure to account for its carbs.
Glycemic Index (GI)
You may have heard that some foods have a “high glycemic index” and others have a “low glycemic index.” A glycemic index ranks foods on a scale from 0 to 100 according to how much the food raises blood sugar levels. Foods are assessed in a lab and compared to pure glucose, which is given a glycemic index of 100. A high glycemic index (greater than 55) means a food spikes blood sugar more rapidly than a food with a low glycemic index (less than 55). To search the glycemic index of foods you typically eat, click here.
While the glycemic index can be helpful for planning meals with diabetes, it’s important to know that it’s not a perfect indicator of exactly how much a food will affect your blood sugar levels. For example, a fruit that is very ripe will raise your blood sugar more than the same fruit that is not ripe (since fruits develop more sugar as they ripen.) The glycemic index also does not take into account how much of a particular food you eat or how that food is prepared.
When it comes to fruit, the fiber found in whole fruits typically brings the glycemic index down.
- Fruits with a low glycemic index include blackberries (4), cherries (20), and grapefruit (25).
- Fruits with a higher glycemic index include pineapple (66), watermelon (76), and dried fruits such as dates (62) or raisins (66).
- For reference, ice cream has a glycemic index of 88.
The plate method
If you use the plate method to manage your diabetes diet, eat a small piece of whole fruit or a handful of berries for dessert. This can accompany your normal plate that’s half full of non-starchy vegetables, one quarter full of protein, and one quarter full of starch. Don’t forget your glass of water on the side!
Other healthy strategies for eating fruit
What else can you do to make sure eat healthy fruit?
- Portion size is key! Make sure you portion out how much fruit you want to eat, and then stick to that amount – this will help you avoid eating too much fruit and experiencing a blood sugar spike. It’s also helpful to spread multiple portions of fruit out over the course of the day, rather than eating a lot of fruit at once.
- Choose fresh fruit whenever possible. Canned fruit, dried fruit, and sometimes frozen fruit often have added sugars (and other chemicals). Processed fruit (like applesauce) also generally contains added sugar.
- Try to avoid fruit juice. Fruit juice contains all of the sugar of fruit without the fiber to help your body process it. This means that juice can cause your blood sugar to spike quickly. If you are drinking fruit juice, drink a very small portion (half a cup) and consider adding water to it; make sure you get “100% fruit juice” so that no extra sugars are added to sweeten the drink. Note: this is why juice can be used to quickly raise your blood sugar if you are experiencing hypoglycemia.
Healthiest fruits for people with diabetes
For those with diabetes, the healthiest fruits are the ones that contain the least sugar. Fruits that are lower in sugar include:
- Berries – blackberries, blueberries, strawberries, and raspberries
Fruits to avoid or limit with diabetes
No fruit should be considered “bad” for people with diabetes, but some fruits have a higher sugar content than others and may affect your glucose levels more. While berries tend to have less sugar, other fruits have more sugar:
- Ripe bananas
- Dried fruit
- Fruit juice