Although scientists are not clear about what causes type 2 diabetes, people can have certain risk factors that include a family history of diabetes, being overweight, and having prediabetes. Fruit does contain sugar, but is unlikely to be harmful to health when it is part of a balanced diet.

In this article, we look at what diabetes is, whether eating too much fruit can cause diabetes and the guidelines on how much fruit a person should eat.

What is diabetes?

Diabetes causes a person's blood sugar, or glucose, levels to become too high. There are two main types of diabetes.

Type 1 diabetes typically develops in childhood, and people with this condition are unable to produce the hormone known as insulin. It is not yet possible to prevent this form of diabetes.

Type 2 diabetes is the most common form of diabetes and can occur at any age but usually develops when people get older. In those with type 2 diabetes, their cells do not respond appropriately to insulin. This lack of response is known as insulin resistance.

Insulin causes sugar to move from the bloodstream into the body's cells, which use it as an energy source.

When a person eats, their digestive system breaks down the carbohydrates in foods into a simple sugar called glucose.

If there is not enough insulin in the body or cells do not respond correctly to insulin, sugar can accumulate in the bloodstream and lead to a range of symptoms and health complications.

Although a person cannot always prevent type 2 diabetes, there are lifestyle and dietary changes they can make that reduce their risk of developing this condition.

Can eating fruit cause diabetes?

Eating too much sugar can cause weight gain, which can lead to higher blood sugar levels, or prediabetes. These are risk factors for type 2 diabetes.

Typically, eating fruit as part of a healthful diet and lifestyle should not increase the risk of diabetes. But consuming more than the recommended daily allowance (RDA) of fruit might mean that a person is getting too much sugar in their diet.

A diet that is high in sugar, refined carbohydrates, and saturated fats is likely to be more of a risk than one that contains moderate amounts of these food types.

Fruit contains many vitamins, minerals, and fiber, so it is a key part of a healthful diet. Choosing fresh fruit rather than dried fruit, and limiting intake of fruit juice or smoothies, can help reduce sugar intake.

Fruit guidelines

How much fruit a person should eat depends on their age, sex, and how much exercise they do. For people who do less than 30 minutes of moderate exercise per day, the United States Department of Agriculture (USDA) recommend the following:

Age Amount per day Children: 2–3 years old 1 cup, 4–8 years old 1 to 1.5 cups, 9–13 years old 1.5 cups; Girls: 14–18 years old 1.5 cups; Boys: 14–18 years old 2 cups; Women: 19–30 years old 2 cups, over 30 years old 1.5 cups; Men: over 19 years old 2 cups

Examples of 1 cup of fruit include:

• 1 small apple
• 32 grapes
• 1 large orange
• 8 large strawberries
• 1 cup of 100% fruit juice

Dried fruit contains more sugar than it does in fresh or frozen form. For example, one-half of a cup of dried fruit is equivalent to 1 cup of fruit in any other form.

People who do more than 30 minutes of moderate exercise per day may be able to eat more fruit than those who do not.

Should at-risk people eat less fruit?

People who are overweight are more at risk of developing type 2 diabetes than those who are not. One of the primary causes of weight gain is if a person eats more calories than they burn off. Sugary foods and drinks are usually high in calories.

Eating the RDA for fruit should not increase a person's risk of diabetes. Fruit juice is particularly high in sugar but drinking no more than 1 cup of fruit juice per day can help keep sugar intake within healthful limits.

Many processed or baked foods, such as biscuits or ketchup, contain added sugar. By limiting these foods, people can reduce their calorie and sugar intakes.

People with prediabetes have higher blood glucose levels than the average but not high enough for a doctor to diagnose type 2 diabetes. Although prediabetes increases the risk of developing diabetes, it does not mean that a person will definitely develop the condition.

It is possible for people with prediabetes to lower their blood glucose and their risk of developing type 2 diabetes.

Losing weight and doing daily exercise can help reduce this risk. Some medications can also decrease a person's risk of developing diabetes.

Can people with diabetes eat fruit?

The American Diabetes Association recommend eating fruit, as part of a healthful diet.

For people with diabetes, a crucial part of managing their condition is their diet, and they often need to plan their meals. They may need to monitor the amount of sugar in their diet, or avoid eating too many carbohydrates.

Fruit contains carbohydrates and sugars. A person with diabetes may want to check these amounts when putting together a meal plan.

As well as sugars and carbohydrates, fruit is high in fiber. Foods that contain fiber take longer to digest, so they raise blood sugar more slowly than those with less fiber.

Foods that contain carbohydrates raise blood glucose levels. Some foods raise these levels more than others.

Some people use the glycemic index (GI) to plan their diet. GI is a measure of how much a particular food raises a person's blood glucose. Foods with a low GI raise blood glucose less than foods with a high GI.

Most fruits are low GI, but some, such as melons and pineapple, are high GI. Processing a food increases its GI, so fruit juice has a higher GI than a whole piece of fruit. Ripe fruit has a higher GI than unripe fruit.

Combining a fruit that has a high GI with low GI foods can make it a healthier choice. An example of this might be slicing a ripe banana and having it on top of whole-grain toast for breakfast.

Dried fruit, fruit juice, and certain tropical fruits, such as mangoes, are higher in sugar. A person may choose to eat a small portion or avoid having these too regularly.

Some canned fruit has added sugar or is served in syrup. Canned fruit that is in fruit juice or low-sugar syrup will contain less sugar than that in ordinary syrup.

Eating fruit in relation to diabetes risk

A 2017 study in China found a significant association between eating fresh fruit and a lowered risk of developing diabetes. Participants with diabetes were also found to have a reduced risk of developing cardiovascular problems if they ate more fresh fruit.

However, the study did not find a specific cause for this association. It could be that people who regularly eat fresh fruit choose a healthier overall diet than those who do not. So, eating fresh fruit may not be enough on its own to reduce the risk of diabetes.

Takeaway

The causes of diabetes are complex, but a person is unlikely to develop the condition solely from eating too much fruit. Being overweight or having high blood sugar are both risk factors for developing diabetes.

Eating fruit in moderation is an integral part of a healthful diet. Limiting the amount of dried fruit and fruit juice in the diet can help reduce sugar consumption.