Books, DVDs, Websites: What’s New?

The Low GI Diet
Revised and updated Australian and New Zealand edition.
Prof Jennie Brand-Miller, Kaye Foster-Powell and Joanna McMillan Price.



‘Can I say how easy the Low GI Diet is to follow, and also The GI Diet Cookbook is excellent. I’ve got so much more energy and feel really well on it.’ – Pernille

The Low GI Diet is the science-based, 12-week Action Plan built around low GI smart carbs and smart moves to help you lose up to 10 per cent of your current body weight. Each week you will have a food goal, an exercise goal, an activity goal plus some food for thought. This revised edition has been updated with more recipes plus your low GI Diet pantry, It also includes:

• The best way to balance protein and carbohydrate
• The tools and tips you need to maintain weight loss for life
• Quick and easy recipes, meal plans and a menu survival guide for eating out
• Simple and practical ways to build more activity into your day
• The at-a-glance GI tables.

ANZ edition: The Low GI Diet, Hachette Livre Australia; Hachette Livre NZ
UK edition: The Low GI Diet, Hodder Mobius
US edition: The Low GI Diet Revolution, Marlowe & Company

Feedback—Your FAQs Answered

What is the law in relation to making a low GI claim on a product in Australia? I have noticed all sorts of claims on various products and seen brands that use a symbol similar to the official GI symbol. I think that this could be rather misleading to shoppers.
Alan Barclay of Diabetes Australia gets asked about this regularly. Here’s what he wrote in a recent issue of ‘Conquest’.

Claims about the GI of foods are currently not regulated under Australian food law. Manufacturers are free to make claims provided they are not false or misleading. They should print the GI value of the food on the food label, to help you to verify the claim. A food with a low GI should have a value less than or equal to 55. There are a number of brands that make low GI claims but do not provide a GI value or definition of what low GI means on the label. Unfortunately, you have no way of verifying whether the claim is legitimate. To do so you’d need to be carrying around the latest version of The Shopper’s Guide, have a mobile phone (call one of Diabetes Australia's dietitians on 1300 136 588) or have internet access through your mobile phone (check the GI database at www.glycemicindex.com). Without verification, it’s probably sensible not to trust the claim because you have no idea whether the food was tested following the standardised procedure by an accredited lab.

You may also see products claiming to be ‘low glycemic’ or ‘diabetic friendly’ leaving it open as to whether it’s low GI, low GL, or low glycemic response. Be cautious with these claims as the product could actually be low carb (check the nutrition label). Manufacturers making these claims may not be intending to mislead the consumer, they simply may not understand the difference. It’s useful to write and ask what they mean and where the food was tested. There are a number of foods that use low GI logos that are similar to the Glycemic Index Tested logo. Some of these cases have been pursued through legal channels.

• Consumers in Australia or New Zealand who have concerns about GI label claims, should contact FSANZ and/or the Australian Competition and Consumer Commission (ACCC).
• Consumers in the USA and Canada can contact the Food and Drug Administration's Office of Compliance at the Center for Food Safety and Applied Nutrition (for USA) and the Canadian Food Inspection Agency (for Canada).

And remember when it comes to reading labels, GI is only part of the picture –don't forget to check the nutrition panel for the fat, salt, and kilojoule/calorie content per serving.


Alan Barclay

The GI Symbol Program: This international symbol is a guarantee that the product meets strict nutritional criteria. Glycemic Index Limited is a non-profit company established to run the GI Symbol Program. Its members are: the University of Sydney, Diabetes Australia and the Juvenile Diabetes Research Foundation. For more information, visit www.gisymbol.com.



I work third shift, four days a week from 2100 to 0600–0700. Sometimes I eat before I go to bed and other times I skip it. When I get up I eat the main meal of the day at 1700–1800 and leave for work shortly after. I have a 15-minute break every two hours and an hour lunch break at 0200 am when I usually eat yoghurt. I have put on weight although I haven’t changed my eating habits. I just don’t know when, how, and what to eat.
Shift work can be a problem, especially for people with diabetes says dietitian Kaye Foster-Powell. Like anyone else who needs to get rid of excess weight, it’s important to talk to a dietitian about total daily food requirements and where and how meals, snacks and activity could be distributed over the day/night. She says that there are a couple of key points that can help shift workers shift excess weight.

The first is sleep. There are studies that show that just small amounts of less sleep than needed (as little as 20 minutes) are associated with weight gain. Here at GI News we aren’t experts on how disrupting the body’s normal circadian rhythm affects biological systems, but weight gain could be simply a consequence of inadequate sleep – 6–7 hours sleep is less than normally recommended for most people.

Secondly, having some structure to meals and snacks also helps. So for someone on third shift, for example, a main at 1700–1800 hours, a snack at 2300 hours, lunch at 0200 and breakfast at 0700–0800 hours would be a useful starting point.

In addition, new research by Medical Research Council scientists at the MRC Laboratory of Molecular Biology in the UK and published in Current Biology has found a major clue to why shift workers suffer from increased incidence of heart disease and metabolic illnesses. The daily ‘body clock’ determines which enzymes are produced by the liver at which time of day and night. This means that the liver’s ability to process meals follows a regular daily progression. Dr Michael Hastings, who led the research, explains: ‘When our body clocks are disturbed (by shift work or jet lag) so as to cause a mismatch between when and what we eat and what the body is able to process at meal times, nutrients are handled less effectively, for example fats will not be cleared from the blood stream and blood sugar levels will not be regulated appropriately.’
– Medical Research Council Press Release
– Current Biology, Vol 16, 1107-1115, 06 June 2006


Kaye Foster-Powell

What’s the GI of a Caffé Latte and Cappuccino?
Most milky drinks will have a low GI and won’t add too many kilojoules/calories either so long as you don’t sweeten them with more than a teaspoon or so of sugar and you say no to those flavoured syrups lined up on the counter. In fact a caffé latte, cappuccino, café au lait or flat white can be the perfect mid-morning snack and an easy way to help you get your two to three serves of dairy foods a day. Regular or skim, milk has a low GI (27–34) – a combination of the moderate glycemic effect of its sugar (lactose) plus milk protein, which forms a soft curd in the stomach and slows down stomach emptying. Regular whole milk is high in saturated fat, but these days there’s a wide range of reduced fat milks including low fat and skim types. If you prefer soy milk (GI 36–45 reduced fat) make sure you opt for calcium fortified and of course, reduced fat. Note that rice milk is not a suitable substitute; it has a high GI (79). How much milk are you getting with your coffee? Well, to some extent it depends on the barista and where you buy it. But here are some standard definitions.

• A caffe latte is a single shot of espresso with steamed milk – approximately a 3:1 ratio of milk to coffee.
• A cafe au lait is similar except it is generally made with brewed coffee instead of espresso in a ratio of 1:1 milk to coffee.
• Cappuccino is traditionally equal parts espresso, steamed milk and frothed milk.
• Flat white is similar to a cappuccino, but with latte proportions of foam.

What’s the GI of cornstarch?
We are often asked about the GI of starchy thickeners from arrowroot and cornstarch, to kudzu root powder and instant tapioca. These silky powders thicken sauces and soups and pie fillings without adding fat or going lumpy. All you do is mix about a teaspoon of the starch into a tablespoon of water, whisk into the liquid you are thickening, and cook for about a minute, stirring constantly to remove the slightly starchy flavour. These proportions will make about 1 cup (250 ml) of a medium-thick sauce. None of these thickeners has been GI tested as far as we know; we haven’t seen any published results. However, you are only using very small amounts diluted in a cup or more of liquid or pie filling. So the GI of the recipe will depend really on what you are making. However, here are some alternative ideas for thickening sauces and soups.

Sauces: Simply reducing the sauce will thicken it and intensify the flavour.
Soups: For vegetable soups, puree some of the cooked vegetables then stir them back into the soup to thicken. Added grated starchy vegetables like sweet potato or yams will also thicken a vegetable soup; or stale, well-crumbled breadcrumbs (sourdough or grainy of course) to a mushroom soup. For a creamy soup you can stir in a little light evaporated milk or low fat yoghurt. Pureed cooked or canned white beans will also thicken a vegetable soup.

In June GI News in the piece on toppings (‘Test Is Best’) you seemed to say that eating fat reduces the GI of a food (and thus would seem to be a good thing). In Feedback in the same issue you seem to say that eating a fat does not reduce the need for insulin and thus presumably does not help one. What’s the story?
It can be confusing. Here are the facts, one at a time.

1. Eating any carbohydrate raises blood glucose and insulin levels.
2. Adding fat or replacing some of the carbohydrate with fat will reduce the glycemic response.
3. But the insulin response is unchanged.
4. We don't want people to lower blood glucose values by adding saturated fats (cheese, butter etc) because that increases the risk of cardiovascular disease. It's much more helpful to choose a low GI carbohydrate food!
5. We don't want people to lower blood glucose values by adding excessive amounts of ANY fat (saturated or unsaturated) because that increases energy intake and compromises weight control. That's not to say that we should avoid good fats, it's a matter a moderation.
6. Mixed meals containing a mix of protein, fat and carbohydrate tend to have a lower GI than single high carbohydrate foods like bread and rice.
7. The glycemic and insulin response to mixed meals can be nicely predicted by (1) the total carbohydrate content of the meal and (2) the GI of the component carbohydrate foods.
8. The usual cut-offs for high, medium and low GI (70, 56 to 69, less than 55) are meant for single high-carbohydrate foods, not mixed meals. Because the range of GI will be narrower for mixed meals, a different set of cut-offs need to be developed. We won't know what those cut-offs should be until we've tested dozens of mixed meals. With the increasing trend to test the GI of ‘meal replacements’, that may not be far off.

The bottom line: In the meantime, our advice is to choose lean proteins, good fats (unsaturated), plenty of fruit and vegetables and good carbs (low GI wholegrains) in the proportions you enjoy. If you are trying to lose weight, control the portion sizes and get a total of 60 minutes of incidental and deliberate activity each day.



Look it up in our A–Z: The GI Glossary (continued)
Ketones Our bodies need to maintain a minimum threshold level of glucose in the blood to provide energy for our brain and central nervous system. If for some reason, glucose levels fall below this threshold, (a very rare state called hypoglycemia) the brain will make use of ketones – a by-product of the breakdown of the body’s fat stores. Ketones are strong acids, and when they are produced in large quantities they can upset the body’s delicate acid-base balance. They are normally released into the urine, but if levels are very high or if the person is dehydrated, they may begin to build up in the blood. High blood levels of ketones may cause fruity-smelling breath, loss of appetite, nausea or vomiting, and fast, deep breathing. In severe cases, it may lead to coma and death. In a pregnant woman, even a moderate amount of ketones in the blood may harm the baby and impair brain development. Large amounts of ketones in the urine may signal diabetic ketoacidosis, a dangerous condition that is caused by very high blood glucose levels.

Ketosis is the metabolic state when the body is burning fat for fuel. Normally carbohydrates are the main source of fuel for your brain, heart and many other organs.

Kilojoule or kJ is the metric system for measuring the amount of energy produced when food is completely metabolised in the body. The Calorie is the imperial measure of energy, and can be calculated from the number of kilojoules by dividing by 4.2.

Lipids or fats are found in the blood and the walls of all of the body’s cells. The most common lipids are cholesterol and triglycerides (sometimes called triacylglycerols).

LDL cholesterol see Cholesterol

Millimole (mmole) is a unit for measuring the concentration of glucose, cholesterol, triglycerides and other substances in a certain volume of blood – usually 1 litre (L).
Mono-unsaturated fat is found in large quantities in olive and canola oil, and some nuts and seeds. Like all fats, mono-unsaturated fats are high in kilojoules. Mono-unsaturated help lower LDL cholesterol levels and are thought to help reduce the risk of heart attack and stroke.

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GI News—July 2006

In This First Anniversary Issue:

• Food for Thought
  —Slow Carb Not Low Carb
  
• GI News Briefs
  —Unite for Diabetes
  —The Rice Factor
  —Foretelling Early Insulin Resistance
  —GI: The Real Meal Deal
  
• GI Values Updates
  —Breakfast Cereals and Beverages
  
• Low GI Food of the Month
  —Do You Have the GI for Fresh Rhubarb Stalks?
  
• Low GI Recipe of the Month
  —Diane Temple’s Sweet Potato and Lentil Bake
  
• Success Stories
  —‘A Low GI Diet – Best Thing I've Done in a Long Time’ Says Lorraine
  —Jaws Drop at the Gym When Margaret Walks In
  
• What's New?
  —Weight Loss for Food Lovers
  
• Feedback—Your FAQs Answered
  
  1. What’s the GI of meat, chicken, fish, eggs and cheese? I can’t find these foods in the GI database.
     
  2. I have heard that pasta made of strong wheat flour (such as durum) has a lower GI than pasta made of softer wheat flour. Is this true?
     
  3. I've been following The Low GI Diet and have noticed some recipes include the use of filo pastry. Does filo pastry have a low GI? I love spinach pastries and even vegetable pies, but I am wondering if pastries have a high GI value?
     
  4. I have read in some GI lists that fresh coconut is low GI, is this true? Coconut does not seem to be on your list!
     
  5. Look it up in our A–Z: The GI Glossary continued
• Events
  —Carbohydrates, Glycemic Index and Health: The State of the Art
  —Dietary Study for Women with PCOS

Welcome to our first anniversary issue. We would like to thank the thousands of subscribers and visitors who have made the newsletter such a success and whose comments and questions have played a key role in shaping the newsletter over the first twelve months.

The GI Group launched GI News a year ago to make available to a broader audience the latest scientific research covering carbohydrates and health (including both positive and negative GI research results), diet and weight loss; diabetes; heart disease; and PCOS along with the latest published GI values. To help people incorporate more of the right carbs into their own diet and lifestyle, we also included information on low GI foods and a recipe or two. And to inspire and motivate we added blood glucose control ‘success stories’. We wanted to hear what our visitors had to say, too. That’s why we set GI News up as a blogspot to allow people to post their own comments or send questions to the GI Group for more detailed answers.

Since posting our first issue on 11 July 2005, we have clocked up around 250,000 visitors and have more than 16,000 subscribers from right around the world. We are pretty proud of this result as we don’t have any sponsorship or advertising dollars to spend on promotion. To receive our free e-newsletter each month, all you have to do is click the SUBSCRIBE link in the right-hand column. Your email address will be kept strictly confidential and you can unsubscribe at any time. We hope you enjoy our first anniversary issue and please pass the link on to friends and colleagues you feel will find the site useful.

GI News Editor: Philippa Sandall
Web Design and Management: Scott Dickinson

Food for Thought

Slow Carb Not Low Carb
In May, ‘News Brief’ reported on a woman who was hospitalised for life-threatening ketoacidosis after following the Atkins diet. We then listed the reasons why we advocated a low GI diet rather than a low carbohydrate diet. Some of our readers admonished us for our stance. Here are their comments and our responses.

1. Opposers of low carb regimes tend to stick to criticism that are really directed to the so called ‘induction phase’ which lasts only two weeks. After that, dieters on Atkins can and should consume a great variety of green, leafy nutritious vegetables, among many others, like mushrooms, eggplant, peppers, broccoli, cauliflower etc. Atkins never encourages you to eat zero carbs. 20 grams for the first 2 weeks, and you raise those levels after that.
   Yes, that’s true, criticism is often aimed at the induction phase but it’s also true that the second phase is restricted in carbohydrates (around 50 grams a day) too, and adherents are encouraged to return to the induction phase (20 grams a day) if weight loss slows. Furthermore, because Atkins recognised that the diet was not nutritionally balanced, a vitamin and mineral supplement program is compulsory.
   
   The study by Yancy et al (Annals of Internal Medicine 2004: 140; 769) compared an Atkins diet with a prudent (low fat but high GI) diet in 120 overweight volunteers. Those following the Atkins diet lost twice as much weight in 24 weeks but read the small print. Specifically, adverse effects occurred more frequently in the low-carbohydrate diet group than in the low-fat diet group, including constipation (68% vs. 35%; P < p =" 0.03)," p =" 0.02)," p =" 0.01)," p =" 0.006)." style="font-style: italic;">Annals of Internal Medicine 2004; 140: 778), two persons on the low carbohydrate diet died, and a third was hospitalised. No such adverse events were recorded in those following the high carbohydrate diet.
   
   
2. There might have been some underlying health reasons for the ketoacidosis you mention.
   The case of a woman who was hospitalised for life-threatening ketoacidosis was written up in The Lancet (Chen TY, Smith W, Rosenstock JL, Lessnau KD The Lancet – Vol. 367, Issue 9514, 18 March 2006, Page 958). The precipitating factor, whatever her individual vulnerability, was strict adherence to a low carbohydrate diet. Fortunately, most people don’t or can’t adhere strictly to the Atkins diet.
   
   
3. No diet is really recommended for ill or pregnant people.
   Pregnant women have to eat and the diet they eat affects their baby’s development. We use the word ‘diet’ in the sense of ‘eating plan’ (as defined by most dictionaries), not restricted energy intake. We agree that it’s not a good idea to restrict energy intake during pregnancy (one reason being the adverse effect of ketones on fetal development). But it’s vitally important that women eat a healthy diet throughout their pregnancy and throughout their reproductive years – because not every pregnancy is planned. A low GI diet fits the bill perfectly, a low carbohydrate diet doesn’t (and you appear to agree). If a diet’s not good for a developing fetus, why would it be good for anyone else?
   
   
4. It is not true that consuming bad fats is unavoidable. You can and should avoid them and stay within Atkins.
   If carbohydrates occupy only 10% of your energy intake (i.e. you eat about 50 grams of carbohydrates per day), then the other 90% of energy must come from a mix of protein and fat. The upper limit on protein intake by humans is around 40% of their calories (kilojoules) because of limits on the liver’s capacity to produce urea. By a process of deduction, that means more than 50% (and more often 60%) of energy comes from fat. Even if you ate a perfectly healthy balanced diet with a P:M:S: ratio of 1:1:1 (polyunsaturated, monounsaturated, saturated fat), you’d be consuming about 20% of your calories as saturated fat. The recommendation is less than 10%.
   
   
5. I love carbs, I could be happy with a GI diet, and I will resort to it as soon as I reach my goal weight, but losing weight with GI diets is complicated because as soon as you surpass the level of carbs you can consume, you stop losing weight and start gaining.
   That was the claim Atkins made but he had no scientific evidence to back that. To our knowledge, there’s still no evidence. Indeed, recent studies suggest that people find it very hard to stick to a diet with so little carbohydrate (too much discipline is needed) and eventually re-gain the weight they lost. Is there any point in losing weight and then re-gaining it? Wouldn’t it be better to align food habits with something that’s not only healthy, helps you lose weight and keep it off for good?
   
   
6. As soon as I can start incorporating more carbs into my diet, they will be of the low glycemic load kind.
   That’s good. Why not cut to the chase early?
   
   
7. There should really be no quarrel between low glycemic and Atkins because they are fundamentally the same. The diets you should be strongly opposing are the low caloric and the low fat diets.
   No, that’s incorrect. Atkins wants to ditch carbs. Low GI diets can be moderately or even very high in carbs, but of the low GI kind. If Atkins had known what we know now, he would have seen ways to lower insulin levels without cutting the carbs. He recognised that high insulin levels interfered with weight control, but he did not have sufficient knowledge to work out the best way to lower insulin. Remember he had no training in nutrition.
   
   
8. The truth is that Atkins works. Once you get to your equilibrium level, then you can do low GL and stay in a narrow weight band.
   Yes, we agree that Atkins works in the short term. But not the long term. So what’s the point in following such a diet?

James Krieger, M.S., M.S. 20/20 Lifestyles Research Associate, PRO Club (http://www.proclub.com) and Editor, Journal of Pure Power (http://www.jopp.us) makes the point that: ‘You lose fat, water, and muscle’ is true of ANY diet. My recent meta-regression, published in the February 2006 issue of AJCN, shows quite clearly that fat loss is significantly higher on ketogenic diets, even after control for energy intake. Fat-free mass loss was also greater, but not by a large amount.


James Krieger

‘There is no apparent metabolic advantage associated with ketosis during dieting’ report researchers from the Department of Nutrition, Arizona State University, Inflammation Research Foundation, Marblehead and Conscious Cuisine, Scottsdale in the May issue of the American Journal of Clinical Nutrition. In summarising their findings, Prof. Carol Johnson says: ‘In the current study, the ketogenic low-carb diet did not offer any significant metabolic advantage over the nonketogenic low-carb diet. Both diets were effective at reducing total body mass and insulin resistance, but, because blood ketones were directly related to LDL-cholesterol concentrations and because inflammatory risk was elevated with adherence to the ketogenic diet, severe restrictions in dietary carbohydrate are not warranted. Furthermore, the nonketogenic low-carb diet was associated with feelings of high energy and a more favorable mood profile than was the ketogenic low-carb diet.’ They recommend anyone wanting to follow a low-carb diet to choose low-fat meats and dairy products, and eat 8–9 servings of fruit and vegetables and 100–125 grams of carbohydrate a day.

GI News Briefs

Unite for Diabetes
During the last 20 years, the total number of people worldwide with diabetes has risen from 30 million to 230 million according to the International Diabetes Federation. The number is expected to reach 350 million by 2025. The top five countries with the most diabetes sufferers in 2003 were India 35.5 million, China 23.8 million, USA 16 million, Russia 9.7 million and Japan 6.7 million.



Facing the facts:

• There are 6 million new diabetes sufferers in the world each year.
• Half of all diabetes sufferers around the globe do not know they have it. In some parts of the world 80% of sufferers don't know.
• Diabetes raises the sufferer's risk of developing a cardiovascular disease by two to four times. Cardiovascular disease, the number one cause of death in the industrial world, will soon be the number one cause of death globally.
• Diabetes is now the fourth biggest cause of death worldwide.
• Every ten seconds someone in the world dies as a result of having diabetes – 3 million deaths a year.
• Good control of blood glucose levels significantly reduces the diabetes patients’ risk of developing complications. Managing hypertension and raised blood lipids is also crucial.

Diabetes is threatening to overwhelm future medical services if left unchecked. The International Diabetes Federation (IDF) is leading a worldwide ‘Unite for Diabetes’ campaign to have the United Nations recognise the global burden of diabetes. Why a UN resolution? If governments begin now by promoting low-cost strategies to alter diet, increase physical activity and modify lifestyles, the advance can be reversed. The proposed resolution would recognise the need for prevention and acknowledge the special needs of children and adolescents, the elderly, pregnant women, migrant populations and indigenous peoples. The aim is for the UN Resolution to be declared on World Diabetes Day 2007 (November 14). For more information about the campaign, visit www.unitefordiabetes.org.
– International Diabetes Federation Press Release from the American Diabetes Association’s 66th Scientific Sessions



The Rice Factor
Heart disease and diabetes are serious health problems in Japan just as they are in many other parts of the world. In fact, heart disease is the second leading cause of all deaths and more than 6.7 million people in Japan have diabetes. Will adopting a low GI or low GL diet reduce the risk? So far, most studies showing the beneficial effects of low GI and GL diets have been carried out in the US, Europe and Australia with people who eat western diets. What happens in Asia where rice is the staple? In Japan, for example, rice contributes 43% to total carb intake and 29% to energy intake (calories).

Japanese researchers have found positive correlations between dietary GI and body mass index, serum triglyceride levels, fasting plasma glucose and HbA1c; and between GL and serum triglyceride levels, fasting plasma glucose and decreased levels of high-density lipoprotein (HDL), or good, cholesterol. They published the results of their cross-sectional study of 1354 healthy Japanese women eating a traditional diet based on a self-administered diet-history questionnaire in AJCN (May 2006). The main contributor to the GI and GL of the women’s diet was white rice (59%) followed by confectionary (11%), fruit (7%), sugars (6%), bread (4%), noodles (3%), other rice (3%), and potatoes (3%). The authors make the point that although the results may not be extrapolated into the general Japanese population (the subjects were selected Japanese female farmers), they should ‘provide valuable insight from a prevention perspective.’
– Am J Clin Nutr 2006;83: 11161–9



Fortelling Early Insulin Resistance
‘Insulin resistance not only predisposes individuals to type 2 diabetes, it is also a major risk factor for cardiovascular disease,’ says Timothy Graham, MD, a researcher at Beth Israel Deaconess Medical Center (BIDMC). ‘In the clinical setting however, it is often difficult to distinguish individuals with and without insulin resistance.’ Insulin resistance develops when the body's muscles, fat and liver cells lose the ability to respond to the hormone insulin.

Elevated levels of a molecule called retinol-binding-protein-4 (RBP4) can foretell early stages of insulin resistance, a major cause of type 2 diabetes as well as heart disease, reveal BIDMC researchers writing in The New England Journal of Medicine.

The researchers were looking to see whether levels of RBP4 correlated with the presence or absence of insulin resistance in three groups and they repeated the measurements after exercise training for one group. They found that RBP4 levels were higher in all cases in which insulin resistance was high. Elevated RBP4 was also closely associated with increased BMI, waist-to-hip ratio, serum triglyceride levels, and systolic blood pressure, as well as decreased levels of high-density lipoprotein (HDL), or good, cholesterol. All the people who improved their insulin sensitivity with exercise also lowered their serum RBP4 levels. Among the third who did not improve their insulin sensitivity, neither did their RBP4 levels go down.



Dr Barbara Kahn

Barbara Kahn, MD, Chief of the Division of Diabetes, Endocrinology and Metabolism at BIDMC and Professor of Medicine at Harvard Medical School says: ‘Collectively, these findings tell us that RBP4 is a useful marker for therapeutic improvement and that this protein could play a causal role in insulin resistance in humans. Because RBP4 levels consistently corresponded with insulin resistance – even among lean subjects whose genetic risk for the development of diabetes might otherwise be overlooked – this protein could be an important marker for type 2 diabetes among the general population. Being able to determine diabetes risk well before the onset of symptoms could provide an important opportunity for patients to take preventive measures,’ she adds. ‘For those who are overweight or sedentary, this could mean making changes to their diet and fitness routines. For those who are lean and fit, but have a family history of type 2 diabetes, this could mean taking antidiabetic medication. Either way, these findings could help clinicians to better manage this growing epidemic.’
– NEJM 354:2552–2563; BIDMC Press Release

GI: The Real Meal Deal
Recent criticism of the GI has focused on unpredictable outcomes of blood glucose values in meals because of variations in fat, protein and fibre levels.

Researchers in the University of Toronto's Department of Nutritional Sciences and the University of Sydney’s Human Nutrition Unit have some reassurance for people with diabetes and carb-counters. The glycemic index (GI), the table that lists the quality of carbohydrates in more than 750 common foods, works just as predictably whether subjects consume a single portion of one item, or a normal meal. ‘The good news it that the GI index works’ says Prof. Tom Wolever. ‘For sensible people it makes a lot of sense. It's simple proportional measure – like mixing paint.’

Concerned about the methodology of recent studies done elsewhere showing unpredictable responses, Wolver and his associate, Prof. Jennie Brand-Miller of the University of Sydney, each conducted studies on two groups of healthy subjects. Fourteen different test meals were used in Sydney and Toronto, and the food combinations reflected typical breakfast choices such as juice, bagels and cream cheese, etc. Despite the variations in food, blood glucose responses remained consistent with GI measures.

‘We had previously done much smaller studies. We revisited the question, using more meals and variety in two different centres with judiciously selected foods. I was startled by the degree of predictability,’ says Wolever. ‘The carbohydrate, fat and protein composition of the meals varied over a wide spectrum. The glucose responses varied over a five-fold range range, and 90 per cent of the variation was explained by the amount of carbohydrate in the meal and the GI values of the foods as given in published GI tables. The concept works.’ The results are published in the June issue of the American Journal of Clinical Nutrition.
– Am J Clin Nutr 2006;83:1306–12; University of Toronto press release

GI Values Update

Breakfast Cereals and Beverages
The latest GI values from SUGiRS.

Breakfast cereal
Morning Sun Muesli GI 49

Beverages
Ribena blackcurrant fruit syrup (prepared with water according to the instructions) GI 52
Schweppes lemonade GI 54



In publishing the GI values of two sweetened drinks, Kaye Foster-Powell reminds parents that they are definitely not an everyday beverage. Here’s why.

‘Liquid calories are a little stealthier than most, in that they tend to sneak past the satiety centre in our brain, which would normally help to stop us from overeating,’ she says. ‘This isn’t to say that we should all avoid full-strength soft drinks, but to keep on the healthy diet food-frequency scale, consumption ought to rank as “occasional”(or even “keep for a treat” if you’re trying to lose weight) and definitely not be everyday. If consumption figures are any indication, an increase in sugar-sweetened soft drinks and cordials is contributing to our child obesity problem. Not only have fatter children been found to have higher consumption, but overall, our children are drinking more of these sweetened drinks than we ever did when we were kids. And of course the increase in serving size from the old fashioned 8 oz (240 ml) to the current 600 ml ‘buddy’ doesn't help. It isn't only soft drinks and cordials that are the problem either. Too much fruit juice, sweetened or unsweetened, is an easy way for us to gulp down extra calories.’

For more information about GI testing at Sydney University, please contact:
Fiona Atkinson sugirs@mmb.usyd.edu.au
Research Manager, Sydney University Glycemic Index Research Service (SUGiRS).
Human Nutrition Unit, Department of Biochemistry (GO8)
Sydney University, NSW 2006 Australia