The lowdown on low carb and low GI
Wednesday, 7 July 2021
The effect of a low carb diet when it comes to diabetes has long been debated. While lower GI carbohydrates are shown to be gentler on your blood glucose levels, deciding whether to follow a low carb diet is your decision. Let’s take a look at what we mean by low carb and low GI eating.
Carbohydrate is a macronutrient and can be found in a complex form, such as starches, or a simple form called sugars. All carbohydrates are digested down to glucose and will increase blood glucose levels (BGLs).
Using the categories found in the Australian Guide to Healthy Eating, foods which contain carbohydrate include:
The ‘core’ foods:
- Grains: Starch
- Milk and yoghurt: Naturally occurring milk sugar (lactose)
- Fruit: Naturally occurring fruit sugar (fructose)
- Legumes: Starches
- Starchy vegetables: Starch
- ‘Sometimes’ foods: mostly added sugars and refined low fibre starches.
The foods in the core food group contain lots of fibre if you choose the wholegrain, whole fruit varieties. All of them contain plenty of vitamins and minerals. They are great sources of nutrition for the body.
The foods in the ‘sometimes’ category taste nice and are part of our celebration days – birthday cake, Easter eggs and Christmas mince pies. But they have also worked their way into our everyday lives – including many takeaways, snacks and very processed foods. ‘Sometimes’ foods have lots of added sugars, fats (including undesirable saturated fats), salt and are low in nutrients. These are the foods that add to our waistlines but not to our health.
Learning to balance the ‘core’ foods with a few of the ‘sometimes’ foods will give your body good nutrition and keep your tastebuds happy while limiting your waistline expansion.
As mentioned earlier, carbohydrate foods will raise BGLs. The more carbs you have the higher they will rise. The easiest way to limit your carb intake is to decrease the ‘sometimes’ foods in your daily eating.
Should I follow a low carb diet?
The research on low carbohydrate diets needs to be long term, and most studies have only gone on for a relatively short time. However, we do know that:
- Low carb eating is not recommended for children (anyone under the age of 18), for people with specialised nutritional requirements such as frail elderly people, and women who are pregnant or breastfeeding.
- For people living with type 1 diabetes there isn’t enough evidence to recommend low carb eating for everyone, but you might choose a lower carb diet if you prefer.
- For people with type 2 diabetes, research has shown that in the short term (up to six months) lower carb eating can help with BGL management and weight-loss, as well as a reduced risk of heart disease. However, the research also shows that after 12 months there is no greater benefit of low carb versus higher carb eating.
It is your decision if you choose a lower carb diet.
What is low or moderate carb intake?
High carbohydrate is more than 225g of carbohydrate daily or more than 45% of total daily energy intake.
Moderate carbohydrate is between 130g–225g of carbohydrate daily or 26%–45% of total daily energy intake.
Low carbohydrate is less than 130g of carbohydrate daily or less than 26% of total daily energy intake.
Talk to your Accredited Practising Dietitian for advice on how to reduce your carb intake if that’s what you would like to do. You may have to decrease your medication if you do, so see your GP for advice on medication changes before you change your diet. If you are on insulin or sulfonylurea medications you could be at risk of hypos if you decide to reduce your carb intake.
What happens if I avoid carb completely?
If you avoid carbohydrates completely you will miss out on valuable nutrients, including fibre, B group vitamins, and potentially a range of other benefits such as vitamin C and calcium.
Our bodies are very clever. Our brains prefer to use glucose as fuel, so the body will produce glucose from fat and protein when it has to. Having a diet high in macronutrients, protein and fat, will lead to this occurring, which will influence BGLs a little.
Are some carbs better than others for BGLs? Yes! Low GI carbs.
This is where low glycaemic index (GI) carbohydrate eating comes in. Low GI foods take longer to digest so they have a gentler effect on your BGLs. These slowly digested foods are more likely to keep you satisfied for longer so you don’t go looking for extra snacks.
Low GI foods include:
Breads, grains, cereals:
- Wholegrain breads and wraps, proper sourdough bread (not just flavoured), basmati or doongara rice, pasta cooked al dente (firm to the bite), rolled oats (not quick oats), muesli and barley-based products.
- Unflavoured milk and yoghurt, oat milk, soy milk.
- Carisma potatoes, potatoes that have been cooked and cooled (yes, you can heat them up again), baby or new potatoes, sweet potato, taro, corn, legumes (peas, beans and lentils).
- Stone fruit, apples, pears, berries.
Check out this website for more info on low GI foods.
How to incorporate low GI eating into everyday
That’s easy! Include one or more low GI foods at every meal or snack.
- Going easy on carb is a choice only you can make: you don’t have to go low carb but moderate carb might be beneficial, at least in the short term.
- Follow your dietitian’s advice and talk to your GP about medications if you do decide to reduce your carb intake.
- When you eat carbohydrates, choose the nutritious carb choices first.
- Low GI carbs will help keep your BGLs stable.
By Dale Cooke APD