I have been hunting for the GI of blackberries, raspberries, blueberries, honeydew melon, tangerine, currants, crab apples, lemon, lime, cumquats, nectarine, plum, rhubarb and have had no luck.
Apologies, to our regular GI News readers who have seen this question in other guises more than once before – it’s a regular to gifeedback. To deal with the ‘where to hunt’ bit first. Check out the database at www.glycemicindex.com, The Shopper’s Guide to GI Values (it is updated annually), use the Google search facility in the right-hand column of every issue of GI News, or thumb through the ‘top 100 low GI foods’ section of Low GI Eating Made Easy.
More importantly, we know that 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. Naturally sweet and filling, fruit is widely available, inexpensive, portable and easy to eat – just like other snack foods, but without the added fat and sugar. In fact, the sugars in fruits and berries have provided energy in the human diet for millions of years. It shouldn’t come as too much of a surprise, therefore, to learn that these sugars have low GI values. Fructose, in particular – a sugar which occurs in all fruits and in floral honeys – has the lowest GI of all. Fruit is also a good source of soluble and insoluble fibres which can slow digestion and provide a low GI. And as a general rule, the more acidic a fruit is, the lower its GI value.
Temperate climate fruits – apples, pears, citrus (oranges, grapefruit, mandarins, tangerines) and stone fruits (peaches, plums, apricots) – all have low GI values. Lemons and limes contain virtually no carbohydrate but provide acidity that slows stomach emptying and lowers the overall GI of a meal so use them to make a vinaigrette dressing or simply squeeze over veggies.
Tropical fruits – pineapple, paw paw, papaya, rockmelon (cantaloupe) and watermelon tend to have higher GI values, but their glycemic load (GL) is low because they are low in carbohydrate. So keep them in the fruit bowl and enjoy them every day if you wish as they are excellent sources of anti-oxidants.
Bananas – these are also tropical and contain more carbohydrate than most other fruits (hence you see them strapped to bikes!). As more and more studies have been done, their average GI has gradually come down to the low 50s. Greener ones will have a lower GI still and riper ones will be higher. As a consequence, their GL is higher than most fruit but don’t give them the flick – they give you a good amount of fibre and plenty of micronutrients, including a big dose of vitamin B6.
Berries – Apart from strawberries (GI 40), most berries have so little carbohydrate it’s difficult to test their GI. So they will have negligible impact on blood glucose levels. Enjoy them by the bowlful.
Dried fruit – Apple rings, apricots, currants, dates, prunes, sultanas etc have low GI values and are a great source of fibre, but the calorie count is much greater than for fresh fruit, so watch portion size. Dried fruit can be very more-ish!
Rhubarb – has virtually no carbs at all, so the GI can’t be measured. If you stew it up with lots of sugar (GI 60) of course, that’s a different story. See GI News July 2006.
How much fruit? One serve is equivalent to:
- 1 medium piece of fresh fruit such as an apple, banana, mango, orange, peach or pear (about 120 g/4 oz)
- 2 small pieces of fresh fruit such as apricots, kiwi fruit or plums (about 60
- 1 cup of fresh diced or canned fruit pieces including grapes and chopped
- berries and strawberries
- 4–5 dried apricot halves, apple rings, figs or prunes (about 30 g/1 oz);
- 1½ tablespoons sultanas (about 30 g/1 oz)
- 200 ml (about ¾ cup) 100% fruit juice, homemade or unsweetened
Well see a doctor and a dietitian have to be numbers one and two on the list. After that? First of all check out March 2007 GI News where dietitian and author Kaye Foster-Powell highlights the key aspects you need to focus on. To get you started, here’s her healthy type 2 diabetes checklist from The New Glucose Diabetes Revolution.
- Use poly and/or monounsaturated margarines and spreads instead of butter and butter blends.
- Use olive and/or canola oils in cooking and for salads.
- Don’t drink more than 1–2 standard alcoholic drinks a day.
- Eat more than 3 cups (300 g) of vegetables every day (this includes soups).
- Eat more than 2 pieces (200 g) of fruit every day.
- Include legumes (canned or dried peas, beans or lentils) in your diet at least twice a week.
- Eat fish (100 g or more) at least twice a week.
- Include low fat dairy products (or calcium-enriched alternatives) in your diet daily and generally avoid full cream types.
- Eat wholegrain and high fibre cereals, breads and grains daily – look for the low GI ones.
- Eat lean red meat (all visible fat trimmed) or poultry (skin removed) in moderately sized (less than 150 g/5½ oz) portions.
- Drink 6–8 glasses of water, or other low kilojoule beverages, every day. Drinking more water won’t lower your blood glucose levels, but high blood glucose means you should drink more water to avoid dehydration.