I am vegetarian and two of my favourite foods – mushrooms and tofu – don't appear in the listings. Can you help?
Mushrooms have so little carbohydrate, the GI can’t be measured. And despite being derived from soybeans, tofu in fact is a protein-rich food with negligible carbs so again the GI isn’t relevant. Eat them to your heart’s content. You may also like to update your bookshelf with a copy of The Low GI Vegetarian Cookbook (by Jennie Brand-Miller, Kaye Foster-Powell and Kate Marsh with Philippa Sandall) et al. It features numerous recipes with tofu and mushrooms (like the one shown below) and shows you how to combine the basics of a healthy vegetarian or vegan diet with the benefits of low GI carbs. You’ll find it in all major bookstores or from Amazon. And to keep up with the latest GI values on a regular basis (for free), check out the University of Sydney GI database at www.glycemicindex.com.
photo: Ian Hofstetter
I have been put on a GI diet but am underweight and need to put on at least 5 kg. I know it is used for reducing weight, but will it help me put on some pounds?
Dietitian Kaye Foster-Powell says: ‘A low GI diet is healthy for you whatever your weight and a higher calorie version could be developed for you to facilitate weight gain. My only reservation is that you may find it difficult to consume the larger quantity of food that would be necessary to increase the calorie value of the diet. It depends on the reason why you are underweight. Have you been sick, do you exercise a lot, lost your appetite or is it simply in your genes? If being underweight is the problem, you have to look at the cause and then explore options to find the best way to address it.’
I have PCOS and know it is genetic. Is there any way I can prevent my baby girl from getting it?
‘This question is a difficult one to answer,’ says dietitian Kate Marsh, author of The Low GI Guide to Managing PCOS and Living Well with PCOS, ‘as there are no specific guidelines for preventing PCOS. We do know that it is genetic and therefore the best thing to do is to eat a healthy diet and be active as a family and hopefully she will adopt these good habits as she grows!
Current research suggests that diets low in saturated fat and high in fibre are associated with a lower risk of diabetes as are diets with more wholegrains and a lower GI. Since the underlying problem in both type 2 diabetes and PCOS (in most cases) is insulin resistance, these findings are also relevant to women with PCOS. We also know that exercising regularly protects against diabetes and improves insulin sensitivity. And of course, a combination of healthy eating and regular physical activity helps with weight management, which also helps with insulin sensitivity. Ensuring your daughter has a healthy rate of weight gain as she grows (not too much or too little) may also help in reducing her risks of health problems including PCOS.
So, the best advice we can give right now is for you to encourage your daughter as she grows to eat a good variety of fruits, vegetables and wholegrains, lean protein foods and dairy products (low fat varieties are not recommended for children under 2 years of age) or alternatives. Highly processed carbohydrate foods and those high in saturated fat and sugar with a poor nutritional value (e.g. sweet biscuits, pastries, chips, lollies and soft drinks) are best kept for occasional treats rather than everyday choices. If you need some more specific advice, make an appointment to talk with a Registered Dietitian (RD) who has experience in PCOS to help you developing a healthy eating plan for her.’
What role should the GI play in an athlete's choice of foods to replenish glycogen storage in their muscles after high exertion?
Dr Emma Stevenson, lecturer in sport and exercise nutrition at Northumbria University in Newcastle Upon Tyne says: ‘Recovery after exercise poses an important challenge to athletes.
The depletion of muscle glycogen stores through periods of high exertion or prolonged endurance exercise provides a strong drive for its own resynthesis. However, carb intake is vital to maximise glycogen resynthesis during the post-exercise period. Muscle glycogen resynthesis is facilitated by both insulin and a rapid supply of glucose. This is why we recommend that athletes consume high GI carbs in the early recovery phase to enhance re-fuelling – approximately 50–100 grams of high GI carbs as a sports drink or snack within the first 30 minutes after exercise. If the recovery time between exercise sessions is longer than 4 hours, the GI of the carbs is less important. Research has shown that endurance capacity during prolonged running was improved and performance in high intensity intermittent running was not effected 24 hours after a low GI recovery diet was consumed compared to when a high GI diet was consumed. So what’s the take-home message? If recovery time is short, consume high GI carbs immediately after exercise to facilitate muscle glycogen resynthesis. If recovery time is longer, the GI of carbs may be less important as long as you consume sufficient carbohydrate.’
Dr Perricone says that one should stay away from high GI foods because they age people. Is this true?
Scientists are beginning to find connections between high blood glucose levels and diseases such as dementia. As we age, abnormal protein deposits form in parts of the brain and eventually interfere with normal mental functioning. High glucose levels accelerate this process. Indeed, the abnormal proteins are called advanced glycosylated endproducts (AGE for short).
To get a feel for how this happens, think about the browning reactions that occur naturally during cooking – think of toasting, baking and grilling. When sugar is present, the reactions occur faster, sometimes leading to excess browning, i.e. burning. The same reactions between sugars and proteins occur very slowly inside the body. Gradually the proteins become burdened by the presence of the freeloading sugar molecules and lose the ability to do their job. When that happens to a long-lived protein like the collagen in skin, the elasticity and natural glow of youthful skin fades. The result: wrinkles. We can’t stop it entirely but we can slow it down.
– Source: Low GI Eating Made Easy available in ANZ (published by Hachette Livre), the UK (Hodder Mobius), and the US and Canada (Marlowe & Company).
Can you give me a list of acceptable low GI fruits. And should one stay away from watermelon and pineapple?
Fruit (and vegetables) play a key role in a low GI diet. The greater the variety the better. 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. As a general rule, the more acidic a fruit is, the lower its GI. Temperate climate fruits – apples, pears, citrus (oranges, grapefruit) and stone fruits (peaches, plums, apricots) – all have low GI values.
Tropical fruits – pineapple, paw paw, papaya, banana, rockmelon 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. Check out ‘The Top 100 Low GI Foods’ in Low GI Eating Made Easy for the lowdown on fruit and ideas for including more in your diet.