A low GI diet is one of few diets that compliments many other eating plans. The main feature of low GI eating is about quality carbohydrates and incorporating plant foods which, according to over 40 years of science, reaps a vast array of health benefits. Incorporating low GI, plant foods into the diet is associated with a reduced risk of various lifestyle related diseases including heart disease, obesity, diabetes, dementia, and some cancers.
If you are following a specific diet and wish to switch to low GI eating, it may be easier than you think. Forget cleaning out the pantry and fridge and spending a lot of money on new foods. Going low GI is more about integrating quality foods into your diet or a ‘this for that’ approach so that you have a diet tailored to your lifestyle and needs while still reaping the health benefits that low GI eating offers.
If you prefer eating Mediterranean or low carb, or if you’re vegetarian, vegan, gluten free or even fasting, a low GI diet can be incorporated into all these eating lifestyles. So, there is something for everyone when incorporating low GI foods into your diet.
What is the Glycemic Index?
The type of carbohydrate we eat affects our blood glucose (sugar) levels. The Glycemic Index (GI) is a tool that measures how different types of carbohydrates affect our blood glucose levels. It is a scientifically proven way to determine which carbohydrate foods are healthiest for us. Carbohydrate foods that are tested are given a score on a scale of 1-100.
- Carbohydrates with a high GI (70+) are digested and absorbed quickly, causing a rapid spike in blood glucose levels.
- Carbohydrates with a low GI (55 or less) are digested and absorbed more slowly at a slower rate, prompting less fluctuation in blood sugars.
- Carbohydrates with a medium GI (55- 69) are digested and absorbed at a moderate rate, causing a moderate rise in blood glucose levels.
An easy way to remember is that low GI foods are less processed and higher in fibre compared to high GI carbs e.g., white bread compared to dense, wholegrain bread or flaky breakfast cereal compared to steel cut oats. Switching to low GI foods does not mean giving up your favourite carbs like bread and breakfast cereal.
Benefits of low GI eating
A healthy low GI lifestyle is a long-term solution to getting healthy. It is a sustainable way of eating to improve overall good health across life stages including [i]:
- Manage weight by controlling appetite, delaying hunger and feeling fuller
- Fuel the body for sustained energy
- Increase physical performance by extending endurance
- Improve concentration
- Reduce the risk of developing type 2 diabetes and heart disease
- Decrease the risk of common diabetes complications
- Benefit eye health and prevent age-related macular degeneration (AMD), a leading cause of blindness
- Improve pregnancy outcomes
- Reduce the risk of breast cancer
- Manage Polycystic Ovarian Syndrome (PCOS)
- Reduce acne
Key Principles of a Balanced, Low GI Diet:
- Include a variety of vegetables and fruit. Most fruits and vegetables are naturally low GI. Choose fruit and vegetables that are in season which will be at their peak nutritionally and cheaper. Fruit and vegetables supply dietary fibre, essential vitamins and minerals and antioxidants. Aim for five serves of vegetables/salad and two serves of fruit each day. At main meals, at least half our plate should include vegetables or salad.
- Include low GI grains. Go for traditional grains like rolled oats, natural muesli, brown basmati rice, prepared sushi made from traditional Japanese rice, pasta cooked ‘al dente’, soba noodles, pearl couscous, buckwheat, quinoa, pearl barley.
- Add legumes. Legumes are high in soluble fibre, low GI, low in saturated fat and cheap! Legumes include chickpeas, cannellini beans, red kidney beans, four bean mix and lentils. If you are not familiar with how to cook with legumes, start by including 1-2 vegetarian meals a week based on legumes. Reducing the amount of animal protein in a meal and adding a can of legumes is an easy way to boost your plant protein intake. Legumes are a delicious, filling addition to salads, soups, casseroles and curries.
- Include healthy fats. Just like carbohydrates, there are better quality fats that are essential to the diet that can aid healthier blood cholesterol levels and lower other cardiovascular risk factors. Healthy fats include olives, olive oil, nuts, seeds, and avocado.
- Include lean protein. Include unprocessed, lean cuts of meat e.g., red meat, pork, lamb, and veal and in smaller amounts i.e., no more than 1-3 serves a week (350g a week). Skinless poultry and eggs can be included more often and aim to include 2-3 serves of oily fish per week [ii].
- Limit white, refined carbohydrates. This includes white bread, white crackers and crispbread and most processed breakfast cereals which are low in fibre and high GI.
- Limit high sugar foods. This includes many packaged and takeaway foods which are often high in saturated fat, trans fats, sugar, and salt. These types of foods should be kept to a minimum and enjoyed occasionally. This does not mean we need to cut out these foods completely. Use the 80/20 rule – include healthy, whole food choices 80% of the time and ‘treats’ 20% of the time. Treat foods include chocolate, cake, biscuits, chips, sweets, and takeaway food.
Low GI Foods Complement Other Diets
The following table outlines how low GI eating complements other diets. For example, low GI foods are an inherent element of a traditional Mediterranean diet. One study found that consuming a Mediterranean diet with low GI foods reduced the daily blood glucose levels in adults at risk for Type 2 diabetes [iii].
| Diet | Low GI Features |
| Mediterranean | Fresh seasonal fruits and vegetables Low GI legumes Low GI grains Healthy fats – olive oil, avocado, nuts, and seeds Lean protein – fish, eggs, lean red meat, and chicken Dairy foods (in small amounts) Mediterranean, low GI recipe: Mediterranean Salmon Traybake |
| Low carb* | Lower carb seasonal fruit Lower carb seasonal vegetables Low GI legumes and grains (you may choose to reduce or omit these) Healthy fats – olive oil, avocado, nuts, and seeds Lean protein – fish, eggs, lean red meat, and chicken Low carb, low GI recipe: Pork Souvlaki |
| Vegetarian | Fresh seasonal fruits and vegetables Low GI legumes Low GI grains Healthy fats – olive oil, avocado, nuts, and seeds Vegetarian protein – eggs, tofu, tempeh Dairy or soy foods Vegetarian, low GI recipe: Low GI Air Fryer Nachos |
| Vegan | Fresh seasonal fruits and vegetables Low GI legumes Low GI grains Healthy fats – olive oil, avocado, nuts, and seeds Vegan protein – tofu, tempeh Soy foods e.g., soy milk, soy yoghurt Vegan, low GI recipe: Carisma Lentil Shepherds Pie |
| Gluten free | Fresh seasonal fruit and vegetables Lower carb potato, sweet potato, corn Low GI legumes Gluten free grains/seeds e.g., low GI rice, buckwheat, quinoa Healthy fats – olive oil, avocado, nuts, and seeds Lean protein such as fish, eggs, lean red meat, and chicken Whole dairy foods Gluten free, low GI recipe: Tom Walton’s One Pot Greek Chicken Rice |
| Fasting**
| Fresh seasonal fruits and vegetables Low GI legumes Low GI grains Healthy fats – olive oil, avocado, nuts, and seeds Lean protein – fish, eggs, lean red meat, and chicken Dairy foods Fasting, low GI recipe: Veggie Protein Loaf |
*Low carb diets refer to reducing the quantity of carbohydrates you eat which means that a low carb food/meal/beverage does not contain much carbohydrate. A low carbohydrate diet or low carb food/meal/beverage will usually include more fat and/or protein. Low carb normally refers to a diet providing less than 130 grams of total carbohydrates per day however different diets will vary with how much they recommend. If you are following a low carb diet, choose quality, low GI plant foods which are high in fibre and reduce the risk of developing chronic disease and some cancers.
**Whilst fasting diets vary, it is more focused on when rather than what to eat, so it’s usually easy to implement low GI foods into the diet.
No matter what eating plan you choose, no matter what your cultural and traditional eating patterns you have, low GI is a lifestyle, rather than a diet, that can adapt to your requirements and deliver a plethora of health benefits.
Written by Rebecca McPhee, Accredited Practising Dietitian (APD) & Health Coach Consultant.
[i] The Glycemic Index Foundation. Quality carbohydrates and health Summary of 20 years of science on the Glycemic Index. 2012.
[ii] www.heartfoundation.org.au
[iii] Bergia, R.E.; Giacco, R.; Hjorth, T.; Biskup, I.; Zhu, W.;Costabile, G.; Vitale, M.; Campbell, W.W.; Landberg, R.; Riccardi, G. Differential Glycemic Effects of Low- versus High-Glycemic Index Mediterranean-Style Eating Patterns in Adults at Risk for Type 2 Diabetes: The MEDGI-Carb Randomized Controlled Trial. Nutrients 2022, 14, 706. https://doi.org/10.3390/nu14030706
