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Almost 40 years ago, David Jenkins and colleagues published the first paper to propose that the glycemic index of foods might be an important measure of nutrition quality. “It was introduced back in 1981 to rate the glycemic character of the carbohydrate in individual foods like bread, breakfast cereal, rice, pasta, apples etc,” says Prof Jennie Brand-Miller. “The purpose was to swap one carbohydrate source with another for snacks and in your meals (e.g. replacing a high GI breakfast cereal like corn flakes with a low one like natural muesli).”

High carbohydrate foods
Choosing good carbs that are low or lower GI for your meals or snacks is now a key dietary choice if you have diabetes. Evidence based recommendations about diet and nutrition from the world’s major diabetes organisations advise people with diabetes to use the GI or GL to help them manage blood glucose levels and reduce their risk of complications including diabetic retinopathy and kidney disease.

Check out the latest findings from two important systematic literature reviews and meta-analyses of randomised controlled trials – considered to be the highest level of evidence.

  • For controlling HbA1c and fasting blood glucose: A systematic review and meta-analysis published in Nutrients in 2018 shows low-GI diets are more effective in controlling HbA1c and fasting blood glucose than higher GI diets and the range of other diets that are typically recommended for people with diabetes including conventional carbohydrate exchange, high fibre and standard diabetic diets. 
  • For reducing risk of type 2 diabetes: A systematic review and meta-analysis published in Nutrients in 2019 shows glycemic index and glycemic load are important markers of food quality and do an excellent job of predicting type 2 diabetes risk for the population as a whole. 

International Federation of Gynecology and Obstetrics also recommend a focus on lower GI foods. “Low GI diets are associated with less frequent insulin use and lower birth weight than in control diets, suggesting that it is the most appropriate dietary intervention to be prescribed to patients with GDM,” they say.

THE GOOD CARBS? These whole foods include milk and yoghurt; fruits and berries; starchy vegetables (potatoes, sweet potatoes, sweet corn); legumes (beans, peas, lentils); nuts and seeds; and grains (oats, rice, buckwheat, quinoa etc) and the traditional staple foods we make from them including noodles, pasta and sourdough and grainy breads.

GOING LOW GI Think of it as adding a filter to your regular healthy eating pattern. First, it only applies to the carb-rich fruits, starchy vegetables, legumes and grains you like to eat. Second, it’s flexible and can be tailored to suit a range of dietary patterns from high carb to low; Mediterranean to Asian; paleo to vegetarian/vegan; gluten-free or low FODMAP. Here’s our 2-step approach to going low GI. 

  • Step 1: Swap it: Replace the high GI foods in your diet with low GI ones. You can find out more about how to do this HERE
  • Step 2: Don’t overload on carbs: Choosing low GI is not a free pass to pile your plate. Keep carb-rich portions moderate so the glycemic load is moderate too. What’s moderate? It’s about a quarter of your dinner plate (inner rim) or 2–3 small lower GI potatoes such as Carisma, GiLicious, Nadine or Nicola, ½ cup diced orange-fleshed sweet potato or corn kernels or baked beans and ⅓ cup cooked basmati or other lower GI rice or al dente pasta. 

Note: The GI does not apply to foods that contain very little carbohydrate like green vegetables, or to protein- and fat-rich foods like meat, fish, chicken, eggs, or cheese that contain no carbohydrate.

Check out the Good Carbs Food Facts story in each issue. We create a complete nutrition information panel for these whole foods and traditional staples made from them along with their GI value and the GL of a typical serving. Use the search box at the top right-hand column of GI News to search for your favourite foods.

Search the International GI Database on the official website for the glycemic index based in the Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders and Charles Perkins Centre at the University of Sydney: glycemicindex.com.

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