1 January 2007

Feedback—Your FAQs Answered

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.

[CHAR-GRILLED VEG]
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!

[KATE]
Kate Marsh

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.

[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).

[HEALTHY SKIN]

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.

[WATERMELON]

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.

25 comments:

Robbo said...

Hello,
I would like to know if grapes and stone fruit are OK for Diabetics. I have trouble keeping a low BSL.
Thanks for any help, Robbo.

gi group said...

Grapes and stone fruits (peaches, apricots and plums have been GI tested) have a low or borderline low/moderate GI. If you want the actual GI numbers for stone and other fruits, check out the database at www.glycemicindex.com or pick up a copy of the latest Shopper's Guide to GI Values (2007). We all need to eat more healthy foods like fruit and vegetables. Most people don’t eat anywhere near enough of these foods. Fresh, dried and canned fruits are all suitable (2-3 serves a day). A serving of fruit isn't very big. It's a couple of small plums or apricots, or a medium sized peach or apple or a handful or grapes. And you can eat most non-starchy vegetables like leafy greens, carrots, tomatoes, onions, etc. freely.

Anonymous said...

I have also been told that oranges & bannanas have a high sugar content that affects diabetics differently. Is this true? I can eat a medium orange and within an hour I feel the difference in my glucose level & when I check it I will have a higher reading then I need. So what is the truth about these types of fruits.

Anonymous said...

I was interested in the article about using carbohydrates to fuel glycogen resynthesis after exercise. Should one eat carbohydrates after exercise even when trying to lose weight? Would it not be more effective to leave a window so that the body is forced to use fat reserves to make up glycogen, then eat at the normal time?

amir said...

What makes brain cells and red blood cells able to use glucose without the need of insulene???

amir said...

Hello,
What are the factors controlling the amount of insulene and what is the role of food acidity on it's effectiveness?

GI Group said...

>>>What makes brain cells and red blood cells able to use glucose without the need of insulin?

The transport of glucose across tissue barriers is mediated by a family of proteins - namely the GLUT (pronounced glute) proteins.

Transport across the blood-brain barrier and across the red blood cell membrane is facilitated by one of these proteins called GLUT1 and does so without the need for any insulin signalling.

The main glucose sink in the body is skeletal muscle. GLUT4 is found in skeletal muscle and is required to transport glucose. GLUT4 requires insulin signalling to function as a glucose transporter.

>>>What are the factors controlling the amount of insulin and what is the role of food acidity on it's effectiveness?

Insulin is secreted by the B-cells of the pancreas. The amount of insulin released is proportional to the amount glucose in the blood stream in a healthy individual. In type 1 diabetes the B-cells do not function correctly and no insulin is released while in type 2 diabetes, excess insulin is produced initially to compensate for insulin resistance. In the end insulin production in type 2 diabetes deteriorates. Food acidity has no bearing on insulin secretion.

hermin said...

"Would it not be more effective to leave a window so that the body is forced to use fat reserves to make up glycogen, then eat at the normal time?"

i think the glycogen resynthesis issue is important mostly with strenuous exercise, but not moderate exercise. in moderate exercise (which i assume would be the type of exercise you are doing), after 15 mins (or so) our body stop using carbs as fuel & switch to fat, so we dont really use up glycogen. however, in strenuous exercise or training, the energy generated by fat is simply not enough to meet our high energy needs. so we have to burn glucose (a.k.a blood sugar) and, when its level goes down, our body breaks down glycogen stores as well, to keep the glucose levels "topped up."

unfortunately we cannot convert fat into glucose (although we do store excess glucose as fat). so we cannot really use our fat stores to top up glycogen. thats why we need to eat carbs after vigorous exercise.

hermin said...

hi there... i'm interested to comment on ur post:

oranges & bannanas have a high sugar content that affects diabetics differently.

i think both of them do contain sugar, (1 medium orange & 1 medium banana contain 10-15 g of sugar) and as u said they affect our body differently since they've got different GI values. generally speaking oranges have lower GI levels than bananas.

I can eat a medium orange and within an hour I feel the difference in my glucose level & when I check it I will have a higher reading then I need.

i can see a few reasons for this:
1. an orange, although may not taste sweet, contains sugar.
2. when u measure ur BGL (blood glucose level) at 1 hr, it is actually reaching its peak by then.

have u heard of "carbohydrate exchange"? some dietitians use this & teach this to people with diabetes to help control their carbs intake, so that their BGL are as stable as possible. in this method, 1 medium orange counts as 1 exchange (while the recommended "exchanges" for AM tea/ PM tea would be 2 exchanges) for example.

Emma said...

"Would it not be more effective to leave a window so that the body is forced to use fat reserves to make up glycogen, then eat at the normal time?"

Hermin is right to comment that we are unable to convert fat into glucose (although we do store excess glucose as fat). so we cannot really use our fat stores to top up glycogen. thats why we need to eat carbs after vigorous exercise.

If you are exercising for weight loss purposes then it may be beneficial to leave a longer time between the end of exercise and eating carbohydrates to maximise fat oxidation. It is however, essential to recover properly from each exercise bout so that you are prepared for the next time you exercise. There is some evidence in the literature that consuming LGI carbohydrates after exercise does not suppress fat metabolism to such an extent compared to when HGI carbohydrates are consumed. This may be a good comprimise between keeping fat oxidation high and restoring carbohydrate stores so that you can perform well in your next exercise session.

Anonymous said...

My husband is 47yrs and has hypertension treated with medication and has recently started developing arrythmias, particularly atrial fibrillation without a pathological cause (cardiologist), also a random blood sugar level of 8.8. The Dr ordered a fasting BSL, 1. should it have been also a glucose loading BSL to check sensitivity? and also would a lower GI diet also have an effect on arrythmias Ta from "New to Site"

hermin said...

thanks Emma for the tips (LGI foods to keep fat oxidation high while restoring glycogen stores, although more slowly) - weight loss "attempters" shouldn't be doing one heavy exercise straight after another (they would be too tired to do it anyway).

hermin said...

hi "New To Site", the Dr might suspect that your husband's hypertension & arrythmias (which might be caused by his heart being "exhausted") have something to do with insulin resistance. if this is true then hopefully low GI will help.

glucose loading ("glucose tolerance test"), i reckon, would be ideal but time consuming & inconvenient for patients. but (as you may think), fasting BSL alone is not enough - its better to do 2-hr post meal too, as a high 2-hr post meal will indicate insulin resistance & diabetes. hope this helps...

Anonymous said...

Hi,It's time to take control of things and after some reading i've decided GI is the way to go. Anything I need to watch out for with the children 3 yrs and 18 mnths both will eat anything i cook for them at the moment, husband same .

Thanks
Kim

gi group said...

Low GI eating for babies and toddlers. We have answered a few questions about this in GI News and you may like to checkout Feedback January 2006 in particular.
A few years ago, Jennie Brand-Miller and Kaye Foster-Powell collaborated with pediatric dietitian Dr Heather Gilbertson and wrote a little New Glucose Revolution guide for Healthy Kids. It's an inexpensive pocket book and you should be able to get a copy from Amazon or order through your local bookshop. A more recent book that includes the top 100 low GI foods is Low GI Eating Made Easy which has a useful chapter called 'Just tell me what to eat!' Here are Kaye's tips to ensure a low GI diet (suitable for grownups and kids).
1. Choose a low GI breakfast cereal. Many big name cereals have a high GI.
2. Choose a low GI bread.
3. Eat fruit for at least one snack and have a milk drink or yoghurt tub for another.

Anonymous said...

Hello,
I have recently been diagnosed with type II diabetes, I am attending classes with nurses and nutrition experts and I asked about GI but the nurse dismissed it saying that GI does not work, because "the index is considered for food taken isolated from others, so it is not a good way to count carbohydrates or sugars"; I felt disappointed because as soon as I started using it to keep control of my sugars, I lost 17 pounds and now I am told this. What should I do?

Thanks for your advice

beruang said...

hi, there seems to be misunderstandings on what is GI & how it works. we don't actually isolate any foods to determine GI; we use the whole food for that.

beruang said...

and i think you are already on the right track as you also have seen the results of following low GI diet.

GI Group, what do you think?

GI Group said...

Re the non-believing nurse.

It's very disappointing when health professionals aren't up to date with the science. But nurses aren't necessarily trained in nutrition. To bring her up to date, why don't you suggest she get hold of a copy of the new US edition (3rd) of Prof Jennie Brand-Miller's New Glucose Revolution which will help her catch up. If you want to 'out' her and send us her address (confidentially to gifeedback@gmail.com) we will ask the US publisher to send her a copy.

In the meantime, you may like to point out that in 2006 the American Diabetes Association fully revised its guidelines for the nutritional management of diabetes and included the use of GI as one of the recommendations. And if you need dietary advice, ask to be referred to a Registered Dietitian with experience in working with people with diabetes and who understands the benefits of low GI eating.

In March 2006 in Food for Thought we ran the findings of Johanna Burani's useful small study that was published in The Diabetes Educator. We quote:
'The participants in the study reduced HbA1c by an average of 19 per cent and BMI by 8 per cent simply by lowering the GI of their meals by 25 per cent (15 points) over the period of the survey (3 to 36 months). Once presented with basic information about incorporating low-GI carbohydrates in meal planning, they made their own decisions and over time converted this dietary change into a way of life to improve their overall glycemia and preserve quality of life.'

sandy said...

describe the findings linking GI and health

Anonymous said...

should GI be the sole criterion for for food selection? why or why not?

gi group said...

Sandy, if you go through the past issues of GI News, you will be able to read summaries of the latest findings about GI and health (the pros and the cons) in News Briefs. Alternatively, buy a copy of the latest US edition of The New Glucose Revolution by Prof Jennie Brand-Miller et al which includes the findings along with the major sources and references.

gi group said...

Should GI be the sole criteria for food selection? No. When choosing foods, the GI is not intended to be used on its own. A food's GI value doesn't make it good or bad for you. The nutritional benefits of different foods are many and varied. Meat and fish are protein rich, wholegrains are rich in carbs, while fruit and vegetables are rich in vitamins, minerals and antioxidants. We suggest you base your food choices on the overall nutritional content, along with the amount of saturated fat, salt, fibre and, of course, the GI value. For more information, check out a copy of Low GI Eating Made Easy.

Mellieee said...

Is there room for the high-GI and medium-GI foods in one's diet?

GI Group said...

Absolutely. There is no need to eat only low GI foods. While you will benefit from eating low GI carbs at each meal, this doesn't have to be at the exclusion of all others. High GI foods such as potatoes and wholemeal bread make a valuable nutritional contribution to your diet and when eaten with protein foods or low GI carbs, the overall GI value of the meal will be about medium.

Keep in mind that when choosing foods the GI is not intended to be used on its own. A food's GI value doesn't make it good or bad for you. The nutritional benefits of different foods are many and varied. Meat and fish are protein rich, wholegrains are rich in carbs, while fruit and vegetables are rich in vitamins, minerals and antioxidants. We suggest you base your food choices on the overall nutritional content, along with the amount of saturated fat, salt, fibre and, of course, the GI value.
What we recommend is a 'this for that' approach, especially when it comes to carb-rich foods like bread, breakfast cereals and starchy vegetables and grains. We find that people who consistently substitute low for high GI foods in their everyday meals and snacks reduce the overall GI of their diet, gain better blood glucose control and lose weight.

If you want some help getting started on low GI eating, why not check out Low GI Eating Made Easy. You will find it in all good bookstores and on Amazon.