GI Update

Professor Jennie Brand-Miller answers your questions



‘What is the latest research on low GI carbs for exercise? Is the intensity of exercise important?’
Whether you are a professional athlete, exercising for health and fitness or aiming to lose weight, the type, timing and amount of food you eat before and after exercise will help you achieve your goals, whatever they are. When you are exercising, your muscles rely on carbohydrate and fat as their main sources of fuel.

• Carbohydrate is stored in your muscles as glycogen, but the stores are limited and about 90 minutes of high intensity exercise will deplete them.
• Fat, which provides the largest nutrient store in the body, can fuel 100–200 hours of exertion, but at a lower intensity.

The relative contribution of carbohydrate and fat as fuel while you are exercising depends on both the intensity and length of your exercise session. Generally, your body’s use of carbohydrate as fuel increases as your exercise intensity increases, and decreases the longer your exercise session lasts. Aerobic training and fitness increase your body’s ability to use fat as a fuel source. This is a plus, as it conserves your limited carbohydrate stores, allowing you to exercise for longer or at a higher intensity.

Our colleague, Dr Emma Stevenson from Nottingham University, does a lot of work in this area. She says: ‘Our research has continually showed that consuming low GI carbs in the hours before exercise can increase the rate at which you burn fat during exercise and also will help to maintain a more sustained blood glucose level. Eating a meal or snack containing low GI carbs 2–4 hours before exercise is what’s usually recommended. The type of carbohydrates that you consume during recovery from exercise depends on the length of time before your next training session. If your recovery time is more than 4 hours then it doesn’t matter what type of carbohydrate you eat or drink as long as you consume enough of it! If recovery time is short, then high GI carbs are useful to replace muscle glycogen concentrations quickly and efficiently. However, research has shown that consuming low GI carbs over a 24-hour recovery period can improve endurance capacity the next day.’

In GI News over the years we have reported several studies that found that milk can be just as effective as sports drinks to aid recovery in athletes. Skim or reduced fat milk (plain or chocolate) also has a low GI and so can be a healthier alternative to sports drinks (yes, even with the added sugar in the chocolate drink).

GI testing by an accredited laboratory North America
Dr Alexandra Jenkins
Glycemic Index Laboratories
20 Victoria Street, Suite 300
Toronto, Ontario M5C 298 Canada
Phone +1 416 861 0506
Email info@gilabs.com
Web www.gilabs.com

Australia
Fiona Atkinson



Research Manager, Sydney University Glycemic Index Research Service (SUGiRS)
Human Nutrition Unit, School of Molecular and Microbial Biosciences
Sydney University
NSW 2006 Australia
Phone + 61 2 9351 6018
Fax: + 61 2 9351 6022
Email sugirs@mmb.usyd.edu.au
Web www.glycemicindex.com

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Lady Gaga fan of the baby food diet

Baby food sales are surging in supermarkets. A Coles spokeswoman said baby food sales had jumped 20 per cent in the past quarter. A Woolworths spokesman said they had experienced a 10 per cent year-on-year jump. Baby food diet advocates claim it is possible to lose 9kg in six weeks when the diet is combined with workouts.

Baby food products are subject to stricter nutrition controls than any other products, limiting salt, sugar and other additives. Pots and packets of baby food often contain between 400 and 600 kilojoules. The Jennifer Aniston version of the baby food diet is said to include up to 14 small pots a day to stave off hunger pangs, plus a regular meal of fish and steamed vegetables.



Dietitian Karen Inge said: "It is not an effective weight loss solution, as it has inadequate levels of calcium, fibre and kilojoules for adults, and is bland, so it will leave them hungry, bored and dissatisfied." The diet's creator is Tracy Anderson, the personal trainer who is also credited with sculpting the figures of Madonna and Gwyneth Paltrow.

Dietpill Nuratrim

She said: "Liquid cleanses do help you lose weight but you will gain more the next week. I wanted something where you can eliminate toxicity, break bad habits but still have your digestive system going. Stars including Lady Gaga, Jennifer Aniston, Reese Witherspoon and Cheryl Cole are believed to have used the baby food diet.

Foods that actually help to speed up your metabolism

Cayenne peppers, jalapenos and habaneros are some brilliant hot and peppery foods that give the metabolism a great big boost. Basically, as well as tasting hot they also get your insides running hot too. These spices will keep boosting your metabolism for roughly three hours after you consume them. So if you’d like a three hour fat burnout then go have a meal with plenty of hot and spicy peppers but just be sure that the meal isn’t too high in carbs and fats.

Salmon, sardines and tuna – these fish are full of Omega-3 fatty acids that will help speed up your metabolism and even have the extra benefit of being very healthy for your heart. Our bodies possess a hormone known as leptin and our metabolism works more rapidly when the leptin amounts are low and these fish help to keep those levels lower, permitting your metabolism to run at a good rate and burn off calories. Fish are also a source of protein and protein is great for speeding up the metabolism.

Whilst on the topic of protein – foods like lean meat, legumes, eggs and also peanut butter will give your metabolism a boost. Peanut butter needs to be eaten in moderation as a result of its high fat content, but do endeavor to incorporate it in your diet as it is rich in both protein and monounsaturated fats. Nut butters are also high in protein, monounsaturated fats and also contain lots of antioxidants. Even though nuts are high in fat, if eaten in small amounts they may actually promote your weight loss.



Whole grains, like oatmeal, are also very good for boosting the metabolism. These foods contain glucose and energy that are much needed for our body and brains to function well, but regrettably many diet plans shun them. They are excellent for boosting the metabolism by regulating the insulin in the bloodstream. They digest slowly and only put a bit of insulin into the bloodstream which keeps things operating smoothly. If your blood sugar levels climb too high then a large release of insulin enters the bloodstream which makes your body attempt to save everything as fat, so it’s important to maintain the insulin levels at a healthy level so your body won’t store up excessive fat. The main reason they are so healthy is because they are rich in fiber which your body attempts to digest and convert to energy despite being unable to. Of course, fiber is also fantastic for digestive health.

Jenny Craig diet program scored top ranking as best diet

Consumer Reports largely based its decision on a recent study revealing that of 332 dieters, 92 percent stuck with the Jenny Craig diet for two years, averaging a loss of about eight percent of their total start weight. Past users say that while using Jenny Craig they were able to lose 2 to 16 times more weight than they were with other dieting systems.

Dietpill Nuratrim

They are also able to keep the weight off for much longer because Jenny Craig shows them how to remain thin as a permanent change to their lifestyle. This is perhaps the biggest difference between Jenny Craig and other weight loss systems; not only do they show their clients how to lose weight quickly and easily, but they teach them how to keep it off well after they have left the program. In fact, Jenny Craig’s main goal is to help people become independent of them- a characteristic quite unique among diet programs

GI News—May 2011

• Jennie Brand-Miller on why gestational diabetes numbers are doubling
• Child obesity – from the get-go, it’s Mum and Dad who can make a difference
• The Australian paradox: sugar consumption down while overweight and obesity increase
• Nicole Senior debunks the ‘people with diabetes shouldn’t eat sugar’ myth
• Emma Stirling on why lollies and candy are OK for treats (as part of a healthy diet)
• Would an insulin index of foods be more useful than GI values?
• 4 delicious recipes for Mother's Day – low GI potato salad with lemon yoghurt dressing, pasta shells with pinto beans, gluten-free mandarin almond cake and Antony Worrall Thompson’s aromatic tomato tart
  

As the second Sunday in May is Mother’s Day in many countries around the world, we thought we would feature stories that highlight why Mum’s diet really matters right from the get-go. Prof Jennie Brand-Miller reports on new guidelines for diagnosing gestational diabetes and what the benefits will be for Mums and babies; scientists from the UK, NZ and Singapore reveal a new link between a mother’s pregnancy diet and her offspring’s chances of obesity; and the findings of the 2-year HIKCUPS study shows that the best way to help overweight and obese kids is to target Mum and Dad and give them good quality advice and support to improve the whole family’s food habits.

Good eating, good health and good reading.

Editor: Philippa Sandall
Web management and design: Alan Barclay, PhD

Food for Thought

Jennie Brand-Miller on why gestational diabetes numbers will double
‘Apart from re-living ‘The Sound of Music’ at the 6th International Symposium on Diabetes in Pregnancy meeting in warm and sunny Salzburg, I learned that the findings of the HAPO Study (Hyperglycemia and Pregnancy Outcomes Study) are changing the way the world diagnoses gestational diabetes (GDM, or diabetes first recognised during pregnancy). One of the following is now sufficient:

• Fasting glucose: above 5.1 mmol/L
• 1 hour post 75 gram of glucose: above 10 mmol/L
• 2 hour post 75 gram of glucose above 8.5 mmol/L

These new guidelines have been accepted by many developed nations and are now in the process of being officially adopted. Using these guidelines will automatically mean that the rate of GDM will increase dramatically. For example, in Australia, this means that about 16% of pregnant women (up from around 8%) will now have a diagnosis of GDM, that’s 1 for every 6 pregnant women. In some ethnic groups, such as South Asian or Chinese women, it will mean 25–30% of women (1 in 3 or 4).

Why have they moved the goal posts? Well, HAPO was one of the biggest studies every done in pregnant women (over 25,000 women from 15 centres in 9 countries). They enrolled only healthy women, specifically excluding those already diagnosed with gestational diabetes according to the old guidelines. The aim was to see if women whose blood glucose levels were ‘intermediate’, that is, high but not so high as to be classed as GDM, were also at risk of having adverse outcomes (e.g. having an emergency caesarean section).

What they found surprised many. There was a very strong link between higher glucose levels and the rate of caesarean section (planned or unplanned), the rate of shoulder dystocia (where the baby’s shoulder is too large for the birth canal) and the chance of having a very large baby, with a weight higher than the 90th percentile. In other words, these women with intermediate BGLs were in need of just as much care as women with diagnosed diabetes, yet as no one thought there was a problem, they were not receiving it.

Another reason why the findings of HAPO were so important relates to what’s called ‘metabolic programming’ and the current epidemic of child obesity. In Australia, like other nations, birth weights have been steadily increasing, and 1 in 5 children is now classified as overweight or obese by only 2–3 years of age. We already know that birth weight correlates with the mother’s BGLs. So, the best way to reduce birth weight, and therefore the likely risk of an overweight child, is to focus on the mother’s BGLs. Ongoing research will determine whether a low GI diet in pregnancy reduces the risk of having GDM or an overweight baby. Stay tuned …’