‘Glycemic index may not affect appetite: Unilever study.’
The story was published in an online newsletter called ‘Food Navigator’ that’s widely read by the food industry and dietitians etc. We don’t know who wrote it, but it is misleading (to put it mildly) as we discovered when we asked Dr Alan Barclay to check it out. ‘First of all, the study wasn’t testing a solid food’ it was testing drinks and drinks on the whole are thought to be less satiating than solid foods,’ he said.
‘In summary,’ he says, ‘it is a poorly designed single study and it is not about GI. It is about glycemic response (not the same thing at all). There are numerous things wrong. Participants were fed between 22–24g carbohydrate for example while standard GI testing around the world (and there is an International Standard) uses 50g of available carbohydrate. In addition, they did not use glucose as a control, so the actual GI values of the test foods could not be calculated so we do not actually know if the various drinks were low, medium or high GI. Looking at the blood glucose response curves in their ‘Figure 1’ in the European Journal of Clinical Nutrition suggests that differences between the GI of each test drink would be minimal, so it’s hardly surprising that they did not affect appetite.
There is level 1 evidence that low GI diets increase feelings of satiety and facilitate long term weight and body fat loss. A systematic literature review and meta-analysis of GI and appetite in 2009 found that low GI meals significantly increased feelings of satiety compared with high GI meals. (Here's the reference: Wati, P. GI and satiety. MND thesis. University of Sydney). Furthermore, the Thomas et al Cochrane review found that “Overweight and obese people lost more weight on low GI diets than on high GI or other weight reduction diets and their cardiovascular risk marker profile improved as well”.’
Two words not in the 2010 Dietary Guidelines for Americans …
‘Glycemic index.’ But we still think that the new guidelines are heading in the right direction. The notable difference between the US Dietary Guidelines (pretty much the same as guidelines around the world) and previous versions is their new recommendation to limit refined grains – not quite on par with statements like ‘reduce added sugars’. To match this statement they need to say something along the lines of ‘reduce added refined starches’. You can read the guidelines HERE.
Pulse power for gluten-free diets
Pulses or legumes are an important part of the healthy low GI way of eating for everybody. They are especially important if you are on a gluten-free diet as they provide much of the fibre and nutrients found in the gluten-containing grains that you can’t eat any more. Dietitian Dr Kate Marsh recommends you put them on the menu at least twice a week – more often if you are vegetarian.
Looking for recipes? Pulse Canada has published a handy 32-page PDF booklet Pulses and the gluten-free diet put together by Shelley Case RD and Carol Fenster PhD. It covers types of pulses (legumes), health benefits, celiac disease and the gluten connection, nutrition on a gluten-free diet, buying storing and cooking pulses and a really practical section on using pulses in GF baking. There are 26 recipes – all photographed (the black bean pizza is pictured here). They haven’t estimated the recipes GI value. You can download it HERE.
The baked recipes use a variety of gluten-free flours including white and black bean flours and yellow pea flour. We asked Peter Watts who is the Director of Market Innovation at Pulse Canada about the availability of these products. ‘You can purchase a number of different pulse flours in grocery stores including pea flour, bean flour, chickpea flour,’ he said. ‘Chickpea flour and some bean flours are available in bulk. Bob’s Red Mill in the US has some nifty packaging with these products in 500 gram bags and they are quite widely available. You can also order on line – a company in Manitoba called Best Cooking Pulses just started selling pea flour and chickpea flours on Amazon. This is not to say that pulse flours are generally available – they are still usually housed in the specialty food section of grocery stores and not all stores offer them, but they are increasingly present. And consumer demand will help increase supply and distribution.’
We haven't been able to track down these flours in Australia or NZ. Let us know if you know where you can buy them.
eBook update: Nutrition for Life
It’s great to see Australian publishers finally embracing eBooks. This best seller by Catherine Saxelby (an early GI supporter) is now available as a digital download as is her Zest cookbook (with Woman’s Day Food Director Jennene Plummer.) We checked out the eBook formats for her books – Kindle and Apple are our favourites for quality and ease of use. We’d give the rest a miss frankly.
Prof Jennie Brand-Miller's GI books will be available in eBook formats soon they tell us. We’ll keep you posted.
- Got Kindle? Buy Nutrition for Life and Eating for the Healthy Heart (or the US edition titled There’s More to Heart Health Than Cholesterol) from the Kindle bookshop on Amazon HERE
- Got Apple? Buy Nutrition for Life, Zest and Eating for the Healthy Heart from iBooks for the iPad or iPhone HERE