Living well

There shall be eternal summer in the grateful heart

In this extract, we find out how and why The CSIRO Low-carb Diabetes Diet & Lifestyle Solution works so well. The diet works because it has been developed using the latest scientific evidence to create an eating pattern that provides an optimal amount and balance of macronutrients for weight and blood glucose control, metabolic health and wellbeing, to maximise the health benefits that can be gained – particularly for people with pre-diabetes or type 2 diabetes. In addition, it also takes into account the individual’s need for diet flexibility.

Eating foods with higher amounts of carbohydrate – such as bread, cereals, rice, pasta, potatoes, many fruits, and foods high in sugar – can cause blood glucose levels to rapidly rise, which can increase the risk of type 2 diabetes and heart disease, along with the health consequences associated with these conditions. This is because all carbohydrates are broken down into simple sugars and released into the bloodstream as glucose.

As shown in the diagram below, high-carbohydrate foods such as bread and jam will give rise to higher blood glucose levels over a shorter time period (peak) with an equally fast drop, compared to foods that are relatively higher in dietary protein (lean meat, fish, chicken, tofu) and healthy fats (nuts, avocado and unsaturated oils).

This is why a meal higher in carbohydrate and lower in fat and protein (such as a white-bread sandwich or toast, apple and a glass of juice) will produce greater blood glucose responses (a rapid spike and fall) compared to a meal with a lower amount of total carbohydrate, and higher levels of protein and fat (such as roast chicken with green vegetables, nuts and cheese), which results in a lower and more stable blood glucose level across the day. ➤

Starchy vegetables Regular and sweet potatoes, corn (fresh or frozen)

Legumes Lentils, beans and

peas

Breads, cereals

and grains such as wheat, oats,

pasta and rice

Whole fruit Fresh and frozen whole fruits and canned fruit in

natural juice

Dairy Milk and yoghurt

Also, when it comes to carbohydrate, the higher the total amount of carbohydrate in a food or meal – and the more refined and highly processed that carbohydrate is – the more it will increase blood glucose.

The degree to which a food or meal will increase blood glucose levels is reflected in a measure known as glycaemic load (GL).

There are two factors that determine the level of glycaemic load: a food’s glycaemic index (GI; in per cent), and the total amount of carbohydrate (G; in grams).

The glycaemic index (GI) is a rating for food, based on the degree to which blood glucose will rise after eating. Foods are given a GI score of 1 to 100, based on the total rise in blood glucose after a reference amount is eaten, compared to pure glucose, which is set at 100. ❱ Low GI is up to 55.

❱ Medium GI is greater than

55 to 69.

❱ High GI is 70 and above.

In other words, the higher the GI scoring of a food, the higher and quicker it will raise blood glucose levels.

Based on the glycaemic load equation, it is clear that simply eating carbohydrate foods with a lower GI is a good strategy to help reduce the overall glycaemic load. However, the other part of the equation is the total amount of carbohydrate.

While both the GI rating and the total amount of carbohydrate play a role in determining the glyceamic load of a food and meal, it is clear that focusing on reducing the total amount (quantity) of carbohydrate (rather than the GI rating) will have the greatest impact on reducing the glycaemic load and blood glucose response after eating. ➤

A good example to demonstrate this is presented below. A typical high-carbohydrate food is rice, with 1 cup of cooked rice providing about 60 grams of carbohydrate.

❱ A high-GI rice with a score of 72 per cent, multiplied by the 60 grams of carbohydrate in 1 cup of rice, equates to a GL score of 43.

❱ This GL score can be lowered to a score of 26, simply by choosing a rice option with a lower GI – in this case 43 per cent – and keeping the amount of rice in the meal the same.

However, the GL score can be lowered strikingly (by ~74 per cent) to a score of 11, simply by reducing the total amount of rice to ¼ cup (or 15 grams of carbohydrate), even if the high-GI rice (with a GI score of 72 per cent) is still used.

This score can be lowered even further by selecting the low-GI rice option. Using ¼ cup of rice with a GI of 43 per cent will give a GL score of about 6.5.

This clearly demonstrates that reducing the amount of highcarbohydrate foods and the total amount of carbohydrate in a meal and the diet will have the largest effect in reducing the glycaemic load and blood glucose response after eating, making it easier to also achieve more stable blood glucose levels throughout the day. This may also mean that you do not need as much medication to control your blood glucose if you have type 2 diabetes.

Other recently published research further supports the benefit of carbohydrate- restricted diets in people with type 2 diabetes, and the findings shown in our CSIRO trial. A recent meta-analysis – a combined analytical summary of several good-quality clinical trials – showed that compared to a traditional high-carbohydrate, low-fat diet, consuming a diet with low to moderate amounts of carbohydrate had greater effects on improving blood glucose control in people with type 2 diabetes – and indeed that the greater the level of carbohydrate restriction, the greater the improvement in blood glucose control. ➤