The scoop on tropical fruit
Emma Stirling APD
You don’t need a nutrition science degree to know that fruit is naturally nutrient rich. At least two serves a day will help boost your vitamin, mineral, dietary fibre and protective antioxidant intakes. But fruit is one food group that’s the cause of GI confusion. Why? Well even though all fresh fruits are labelled healthy, many tropical fruits are stamped with a moderate to high GI. But does this mean that you should bypass a juicy pineapple? Let’s explore. And before you GI pros jump ahead, read on as we have a new GI value to share (durian!).
Feeling fruity Now as you know it’s really tricky to predict the GI values of any food without laboratory testing. Right? But with fresh fruit, there are some factors that can guide us:
Going troppo It’s true that temperate climate (often referred to as orchard) fruits tend to have a low GI. So you can snack with confidence on apples (GI 38), pears (GI 38), citrus like oranges (GI 42) and grapefruit (GI 25) and stone fruits like peaches (GI 42)and plums (GI 39). But when it comes to tropical fruit, things go a little troppo:
- Type of carbohydrate: fruits with a higher ratio of fructose to glucose will have a lower GI.
- Acid levels: the more acidic a fruit, the lower the GI value.
- Dietary fibre content: fruits higher in soluble and insoluble dietary fibre (keep the skins on where possible please) help slow digestion and promote a lower GI.
Mangoes (GI 51) and bananas (GI 52) are two of the few tropical fruits with a low GI. Pineapple (GI 59), paw paw (GI 56), rock melon/cantaloupe (GI 68) and watermelon (GI 76) tend to have moderate to high GI values. But remember it’s worthwhile to consider the glycemic load (GL) in these few instances. We touched on the type of carbohydrate above, but the amount of carbohydrate you eat at any meal or snack is also key to effective blood glucose control. The glycemic load of these tropical fruits is in fact low, because they are low in total carbohydrate content and high in water. That’s what makes them their juicy best. So isn’t that great news? You can still cool down with a slice of watermelon in the heat of summer – just watch your portion size.
Thanks to new data published in the Asia Pacific Journal of Clinical Nutrition we now know that one very tropical fruit, durian, has a low GI (49). Durian you ask? Well this is one fruit that you need to smell it to believe it. This heavy, soccer ball-sized, spiky fruit has a very pungent odour. And in my opinion I’m yet to meet anyone that eats enough durian to remotely worry about its GI. Revered in Southeast Asia as the “king of fruits” and described as “fragrant”, it remains very much an acquired taste elsewhere. Ripe durians are eaten fresh but have a short shelf life. In cooking they are used for preserves (jams and pickles), milk-based desserts and ice-creams, cakes, and confectionery; in some parts of Asia unripe durians are used as a vegetable. But in some South East Asian hotels durian are banned as the odour is so off-putting to foreign guests.
Mix it up Whatever your likes or dislikes, feel confident with all fruit. Mix up your fruit bowl for plenty of variety including other luscious, bright pigmented, tropical faves like guava and dragon fruit. And favour your local seasonal, regional produce. Research shows people who eat three or four serves of fruit a day, particularly apples and oranges, have the lowest overall GI and the best blood glucose control around town (or tropical jungle).
Emma Stirling is an Accredited Practising Dietitian, health writer and editor of The Scoop on Nutrition – a blog by dietitian experts. Check it out or subscribe for hot news bites and a healthy serve of what’s in flavour.
GI Group: Are any engineers listening? Prof Jennie Brand-Miller would love to buy a fruit bowl that kept fruit on the bench or table cool and in the line of sight of hungry children.