Going low carb: complete guide to low carb diet

Low carb diets have become hugely popular in recent years, and the range of products and recipes advertising their lower-carb or keto virtues has exploded.

What does it all mean, and should we all be going low carbohydrate?

Carbohydrates are energy-yielding nutrients (macronutrients) that are the body's primary source of energy.

The tricky thing about ‘low carb’ is that there isn’t an agreed consensus on what ‘low carb’ actually means. Most dietary guidelines recommend that carbohydrate contributes between 45–65 per cent of your energy intake, which is a pretty big range. This is generally considered a moderate or balanced carbohydrate intake. In many research studies, a low carbohydrate diet generally offers between 20–45 per cent of its total energy from carbohydrate, which is also a pretty big range.¹

So, because the definition of a low carb diet depends on the proportion of energy that it contributes to, the amount of carbohydrate you can consume on a low carbohydrate diet is very dependent on your energy needs.

• For example, for a 70kg woman who exercises three times a week and needs 9,240kJ (2,200 calories) per day, a low carbohydrate diet consists of consuming 110–250g of carbohydrate per day.
• In contrast, a 90kg, active man, who needs 12,600kJ (3,000 calories) per day, can afford to have 150–340g of carbohydrate per day and still be adhering to a low carbohydrate diet.

There are many reasons why low carbohydrate diets have become so popular.

Implementing a low carb diet: energy

Since the re-emergence of the Atkins diet in the mid-90s, there has been a cultural push toward reducing carbohydrate to manage energy intake and weight. As carbohydrates are a key nutrient that fuels your body, removing or reducing high carbohydrates food can reduce your energy intake.

For example, if you swap from having one cup of cooked basmati rice with your dinner (approx. 400 calories) to 1 cup of cauliflower rice (approx. 40 calories), the energy content of your meal reduces and can contribute to an energy deficit, which is required for weight loss.

While this sounds encouraging, it’s important to remember that your overall energy intake is an essential component to weight loss. If you end up consuming lots of fat and protein-rich foods instead of carbohydrates, and your total energy intake is too high, long-term, sustainable weight loss won’t be achieved, regardless of how low your carb intake is.

Managing type 2 diabetes

One of the most promising aspects of the research into low carbohydrate diets is that they appear to improve markers of insulin resistance. Several reviews of the dietary approaches to manage type 2 diabetes indicate that moving from a moderate or high carbohydrate diet to a low carbohydrate diet can improve blood glucose control and even push diabetes markers into remission.^2,3

As with any dietary pattern, the results will only last as long as we continue that dietary pattern. This is why it’s important to work with a dietitian to determine the right load of carbohydrate that can be sustained within your lifestyle, and avoid falling for myths about diabetes and nutrition.

Ketogenic diet

‘Keto’ or a ketogenic diet is a common reason why people are looking for low carb options. A ketogenic diet is very low in carbohydrate (less than 10 per cent of energy coming from carbohydrates) and it requires the elimination of a range of healthy whole-food groups including grains, legumes, fruit, starchy vegetables and dairy products. The removal of these foods can have implications for gut health, nutrient deficiency and metabolic health, which is why it’s important to consult with a healthcare professional before commencing a restrictive dietary pattern.

If you are wanting to reduce your carbohydrate intake, these foods are naturally lower in carbohydrate and can be nutritious options.

Low carb vegetables

• Spinach
• Bok choy
• Broccoli
• Green beans
• Carrots
• Parsnips
• Turnip
• Tomato
• Cauliflower
• Peas
• Capsicum
• Onion
• Cucumber
• Radish
• Pumpkin
• Zucchini
• Eggplant
• Mushroom
• Wombok
• Cabbage
• Snow peas

Low carb fruit

• Blueberries
• Strawberries
• Blackberries
• Plums
• Kiwi fruit
• Cherries
• Rockmelon

Nuts and seeds

• All nuts and seeds are low in carbohydrate.

Meat, poultry, seafood, eggs and soy

• All foods in these groups are low in carbohydrate unless they are crumbed, battered or marinated.

Dairy

• Milk
• Yoghurt – unsweetened
• Cheese

Remember

Lower carb doesn’t mean no carb. Nearly all foods contain carbohydrate as it’s a necessary nutrient for metabolism.