Professor Jennie Brand-Miller answers your questions
Some people tell me that watermelon sends blood glucose levels soaring, but others say that’s wrong. What’s the real deal?
The real deal is that a normal serving of watermelon won’t have much effect on blood glucose levels. Those who’ve got it wrong are taking the high GI value of watermelon in isolation. It’s important to consider the amount of available carbohydrate in a typical serving as well as the GI value. Watermelons and other melons such as rockmelon (cantaloupe) are high GI foods, but are relatively ‘dilute’ sources of carbohydrate. In fact they only have about 5% available carbohydrate, which makes their glycemic load or GL per serving very low. A low GL means minimal impact on your BGLs. Both melons in moderate servings are an excellent snack and quite thirst quenching too. Here’s how the numbers add up:
- Watermelon has a GI 78, but a wedge without skin (about 200g) contains 6g available carbs and will have a GL of 6
- Rockmelon/cantaloupe has a GI of 88, but a cup of diced pieces without skin (about 200g) contains 7g available carbs and will have a GL of 8
‘I purchased your book The G.I Factor – the Glucose Revolution Revised 2nd Edition about 4 years ago. I never read it and had it sitting on my bookshelf for all those years until about a month ago. I had tried many methods of losing weight with complicated recipes and even tried the Tony Ferguson for one month and piled it all back on with twice more. I started reading your book and it all started to make sense why my body was not responding to all those gimmicks.
I started to make a few of the dishes and really enjoy them (especially the Swiss muesli for breakfast) and have since about a month ago really started to plan my meals a great deal more. On Sunday afternoons I have a big cook where I make at least two dishes to have during the week. The meals are all simple and delicious and even my family are starting to enjoy them.
I have also purchased the The New Glucose Revolution – LifePlan and again enjoy the recipes at the back especially the Mediteranean Lasagna. Big thumbs up from my family. I saw my GP today and he is very happy with my weight loss which has now been 6 kilos. I have more energy, go to the gym at least 4–5 times per week and enjoy the variety of classes at the gym.
A lot of staff at work have also commented on my weight loss and want to know my secret. I have shown them your books and I’m hoping to inspire all of them to take up the GI way of eating. I have another 15 kilos to go but with the right tools (recipes) determination, support from my family, friends and residents and staff at work I’m sure I will get there.
I have diabetes on my mother’s side of the family and had gestational diabetes with my second son so I’m a prime candidate for diabetes. I’m a Community Speaker for Cancer Council and one of my presentations is about the risk factors of cancer and touches on obesity and promotes the waist measurement campaign. So I’m determined to be a living success story and hope to inspire lots of people around me.’
New GI values from Fiona Atkinson at SUGiRS for breakfast and snack foods
Carman’s breakfast cereals and bars
(Serving sizes here are as per product label.)
- Traditional Australian Oats (made with water) – GI60 (available carbs 28g per serve, GL17)
- Deluxe Fruit Muesli – GI51 (available carbs 19g per serve, GL10)
- Yoghurt, Apricot & Almond Bar – GI44 (available carbs 18g per serve, GL8)
- Dark Chocolate, Cranberry & Almond Bar – GI53 (available carbs 19g per serve, GL10)
- Apricot & Almond Muesli Bar – GI51 (available carbs 23g per serve, GL12)
- Mixed Berry – GI30 (available carbs 32g per 1 cup /250ml serve, GL10)
- Mango Passionfruit – GI25 (available carbs 32g per 1 cup/250ml serve, GL8)
- Strawberry – GI30 (available carbs 32g per 1 cup/250ml serve, GL10)
- Tropical – GI25 (available carbs 32g per 1 cup/250ml serve, GL8)
GI testing by an accredited laboratory
Dr Alexandra Jenkins
Glycemic Index Laboratories
20 Victoria Street, Suite 300
Toronto, Ontario M5C 298 Canada
Phone +1 416 861 0506
Research Manager, Sydney University Glycemic Index Research Service (SUGiRS)
Human Nutrition Unit, School of Molecular and Microbial Biosciences
NSW 2006 Australia
Phone + 61 2 9351 6018
Fax: + 61 2 9351 6022
See The New Glucose Revolution on YouTube