While health authorities encourage the “5-a-day” rule—aiming for at least three servings of vegetables and two servings of fruit daily to ensure adequate vitamins, minerals, and dietary fiber—nutritionist Li Wan-Ping cautions that not all fruits are suitable for unlimited consumption. She specifically highlights five fruits that raise blood sugar the fastest and emphasizes the importance of portion control.
Li points out that watermelon, with its high water content, spikes blood sugar levels the quickest. She recommends limiting consumption to one bowl per day and avoiding watermelon juice. Pineapple, which becomes sweeter as it ripens, can send blood sugar on a roller-coaster ride; a portion the size of two palms is suggested daily.
Bananas with black spots on the peel indicate that starch has converted to sugar, which can elevate blood sugar sharply; one banana per day is sufficient. Mangoes, being very sweet, should also be limited to one bowl per day. Small, sweet grapes can be easy to overeat—Li recommends a maximum of 10 grapes per day.
Regarding timing, Li explains that fruits with high water content, such as peaches, pears, and wax apples, can be eaten before meals to promote satiety. Conversely, acidic fruits like oranges, tangerines, and strawberries can stimulate stomach acid, so they are better avoided on an empty stomach. Fruits containing digestive enzymes, such as pineapple, papaya, and kiwi, are best consumed after meals to aid digestion. Other fruits with milder effects, like grapes and guava, can be enjoyed either before or after meals.
