Last week, an elderly gentleman sat at my table lamenting his high blood glucose values. “I have always been well controlled. But over the past three months, my sugars have skyrocketed. I am very careful with my lifestyle. There is only one change I have made to my diet. I have replaced two meals with fruit. This has increased my fruit consumption. They are the healthiest and most natural foods you can eat. They can’t spike my sugar, can they?
What is the correct answer to my patient’s question? Fruits are said to be nature’s sweets, full of sweetness. Most of us love fruit because it looks and tastes good and we feel (rightfully so!) that it is good for our health. Fruits are an important part of our diet as they contain numerous vitamins, minerals and antioxidants such as polyphenolic flavonoids, vitamin C and anthocyanins. These compounds not only protect the human body from oxidative stress from free radicals, but also increase the body’s immunity level.
Many fruits are rich in fiber, which plays an important role in managing our sugar levels. A diet high in soluble fiber slows the absorption of sugar. Plus, fiber makes us feel full, so we eat less. Fruits have a lot of water, which improves hydration. Both the fiber and water in the fruit help fight constipation, a common problem in people with diabetes. Diets containing adequate amounts of vegetables and fruits reduce the risk of obesity, high blood pressure, heart attack, stroke and cancer.
So can people with diabetes eat fruit generously? Or, because of their inherent sweetness, fruits are a strict no-no in diabetes? The truth, as usual, lies somewhere in between. First of all, any fruit can be consumed by a person with diabetes. Second, not all fruit is created equal, and recommended serving sizes vary greatly by glycemic index (GI). The GI is a food score on a scale of 1 to 100. The higher the score, the faster the absorption and subsequent rise in blood sugar. Third, the most beneficial effects of fruit are only seen with fresh fruit and not with canned or processed fruit, many of which contain added sugar and may be depleted of nutrients. Fourth, fruit juices are not the same as fruit. In fact, they contain only the sugary part of the fruit without the fiber, are much less nutritious and raise blood sugar.
Which fruit and how much is advisable for people with diabetes? The key to fruit consumption in diabetes is to incorporate them into the daily amount of carbohydrates. So if you’re going to add fruit to your diet, you’ll need to cut back on other carbohydrates. The amount of carbohydrates present in the fruit determines the impact on the blood sugar level. For people with diabetes, a serving of fruit should contain 15 grams of carbohydrates and the total daily intake should not exceed 30 g. So you can have a 15g carb serving of fruit at once and a total of two servings of fruit per day. It is preferable to eat fruit as a mid-morning or mid-evening snack rather than as an after-meal dessert, as it adds to the carbohydrate load. Instead of consuming large portions of fruits, it is best to combine them with protein-rich foods such as dairy products or nuts. Since fruits have no protein, this makes the snack more nutritious and filling.
The glycemic index also helps us choose our fruit, because it reflects the rate of increase in blood glucose. Examples of low GI fruits (GI 20-49) include apples, avocados, cherries, guava, peaches, pears, and strawberries. Medium GI fruits (GI 50-69) include figs, grapes and oranges. Bananas and fully ripe dates are examples of high GI fruits. The serving sizes of different fruits that provide 15 g of carbohydrates are shown in the table.