Why do we feel full after a bowl of oats, yet chomp through a whole packet of rice crackers and easily have room for more? HFG investigates the fullness factor.
We’ve all experienced the frustration of a meal that doesn’t really satisfy. Even though you’ve polished off everything on your plate, you soon find yourself back in the kitchen in search of another bite to eat.
If you’re searching for the key to keeping hunger pangs at bay, the answer is simple: the glycaemic index. Here’s everything you need to know!
Carbohydrates get a bad rap, but it’s important to realise they’re not all created equal.
The glycaemic index (GI) is a number between 1 and 100that measures how quickly or slowly a food that contains carbohydrates affects your blood glucose levels.
The carbohydrates in rolled oats, for example, are digested slowly, leading to a gradual rise and fall in blood glucose levels — so they have a low-GI rating.
By comparison, the carbohydrates in high-GI foods are broken down quickly. Think of high-GI foods as your blood glucose levels taking a ride on a rollercoaster, with a rapid spike and then crash soon after eating. The sudden rise in blood glucose levels puts pressure on your body to produce more insulin, which over time can lead to type 2 diabetes.
High-GI foods also contribute to slumps in energy levels, followed by cravings for sugary foods, which sets in motion a dangerous cycle.
Low-GI diet benefits
Sticking to a low-GI diet brings with it a host of health benefits. Since the early 1980s, when the concept of GI was introduced, research findings have confirmed that the low GI method of weight loss and fat loss holds up. A low-GI diet is also routinely recommended by GPs and other health professionals to help manage type 1, type 2 and gestational diabetes.
Plus, a low-GI diet provides more sustained energy, keeps your metabolic rate healthy, and helps manage hunger and cravings — because low-GI foods are naturally more filling.
High GI: 70 and over
Medium GI: 56–69
Low GI: 55 and under
What ‘glycaemic load’ means
GI measures the quality of carbs, whereas the glycaemic load (GL) considers quantity and quality of carbohydrates. This means that if you consume a large portion of low-GI foods in one sitting, your body still has to work hard in order to digest all of those ‘good’ carbohydrates. So, the best approach is to eat small portions of low-GI carbs.
The GI isn’t the only thing to consider when you’re thinking about carbs. Whole grains such as oats, grainy bread or brown rice are far more nutritious than their refined counterparts. The reason is that whole grains have all three layers of the grain intact, providing fibre, heart-healthy fats and antioxidants.
Whole grains are also associated with a range of impressive health perks such as reduced risk of early death, heart disease and some cancers.
5 reasons to low-GI foods
Feel full for longer
Low-GI foods are digested slowly, so they’ll keep you feeling full —and you’ll be much less likely to overeat.
Get more energy
In contrast to a short burst of energy from high-GI foods, low-GI foods give you long-lasting energy that will help power you through the day.
Look after your ticker
Many low-GI foods are high in gut-loving fibre, which can help reduce ‘total’ as well as the ‘bad’ LDL cholesterol that lifts your risk of heart attack and stroke.
Trim your waist
Together with foods that are protein-rich, a low-GI diet can reduce your insulin levels and also burn body fat, helping you to achieve and maintain a healthy body weight.
Manage your blood glucose after meals
If you have diabetes, low-GI foods result in more stable blood glucose levels, which in turn reduces your risk of later developing long-term complications.
Hit the shops!
Here’s your low-GI shopping list:
Natural or untoasted muesli
Basmati or Doongara rice
Starchy vegetables, such as orange sweet potato, sweet corn and peas
All other non-starchy vegetables, like tomato, mushrooms and carrots
Fruit, especially berries, apples, bananas, kiwi and stone fruit
Canned or dried beans, chickpeas or lentils
Your low-GI day on a plate
Breakfast: Natural muesli with plain reduced-fat yoghurt and mixed berries
Morning snack: 30g raw unsalted nuts and chopped vegetable sticks
Lunch: Wholegrain wrap topped with barbecued skinless chicken breast, salad vegies and hoummos
Afternoon snack: Homemade smoothie made of reduced-fat milk, almonds and banana
Dinner: Baked salmon with brown basmati rice and stir-fried Asian greens
Melissa is an Accredited Practising Dietitian with a love of healthy, delicious food. She is passionate about helping others to lead healthier lives and teaching people to use nutrition to better their health.