By Aleksandra Savic: final year Nutrition and Dietetic student

Reviewed by Rebecca Greco, Accredited Practising Dietitian, MND, B.HlthSci (1A)

It’s hard to keep track of the popular opinion about carbohydrates these days, with so many different voices in the media telling us the ‘best’ amount of carbs for our bodies. Some celebrities and bloggers promote diets containing low or almost no carbs claiming that is it good for health and/ or weight loss. However, this practice doesn’t add up with the Australian Dietary Guidelines (ADG). The ADG are a set of evidence based dietary recommendations that promote eating a wide variety of nutritious foods for good health.

Below is some basic information about carbs to help you understand the role they play in our body.

What are carbohydrates?

Carbohydrates is not just found in bread or pasta! They can be found in many foods, including:

• Cereals
• Rice
• Pasta
• Grains (e.g. barley, couscous)
• Fruit
• Legumes
• Bread
• Vegetables such as sweet potato and corn.

Carbohydrates are a macronutrient that provide our bodies with energy and are split into three main categories: sugars, starches and fibres.

Sugars are found naturally in fruits and milk products, but they can also be added to sweeten foods during processing.

Starches are made of many sugar units linked together, which are then broken down by digestive enzymes. Starches are found in foods such as vegetables, legumes and grains.

Fibres are also made of many sugar units linked together, however they cannot be broken down by our digestive enzymes.³ While fibre is not mainly used by our bodies for energy, it is important for maintaining good gut health, reducing the risk of chronic diseases and helps with weight control.

Are low-carb diets a healthy option?

Some popular versions of low carbohydrate diets you may have heard of are the ketogenic (keto) diet, the Atkins diet or the Low-Carb, High Fat (LCHF) diet. So why would people want to cut down their intake of our most important energy source?

The theory behind a low-carb diet is that with the reduction of the amount of sugar and starch in the diet, there is also a reduction in insulin secretion (a hormone produced by the pancreas) and the body switches to burning fat. This is called ‘nutritional ketosis’, as fatty acids are converted to ketone bodies to provide the body with energy. It is important to note that the claims for the low-carb diet are therefore mainly related to weight loss, rather than being something that that the general public should adopt as a lifestyle.

While there are studies showing that low-carb diets can be effective for weight loss under the supervision of an Accredited Practicing Dietitian, there are also some concerns to consider. Starting a low-carb diet will often come along with muscle cramps, loss of energy, bowel changes and bad breath. Another major concern with a low-carb diet is that vegetables, fruit and grain intake is reduced, only to be replaced by an increase in foods that are high in fat . Long-term, this could  promote weight gain, while there are also studies that suggest there may be an increase in LDL or ‘bad’ cholesterol levels which overtime is not good for our heart health.

A recent systematic review suggests that low-carb diets are not any not more  effective at reducing weight than a balanced weight loss diet (a diet that restricts total energy while keeping a balance of food groups). Another review found weight loss in low carb diets was  as a result of a decreased calorie intake and longer diet duration, rather than  a reduction of  total carb content. The low-carb diet is also really difficult to sustain, with very limited evidence about the diet for use over a long period of time.

Overall, there isn’t enough evidence out there to suggest that low-carb diets should be widely recommended as a safe way to lose weight. While there may be some individuals who benefit from this diet, the risks should also be considered. Advice can be sought from an Accredited Practicing Dietitian for an individualised and sustainable way to lose weight. If you’re not trying to lose weight but have the opinion that ‘carbs are bad’, don’t forget that they are an important energy source! Getting rid of carbs is also likely to reduce your intake of many foods that contain important vitamins, minerals and fibre which are important for overall health.

Healthy carb eating

Here are three key tips that can help you to have a healthy relationship with carbs:

• Choose wholegrain varieties (e.g. wholegrain bread, – They contain more fibre, vitamins and minerals.
• Limit the intake of foods containing added sugars – Foods with added sugars increase the energy content while diluting the nutrient intake.
• Choose high fibre options – Where possible, choose food products that contain 3g or more of fibre per serve

Links for more information:

Australian Dietary Guidelines

Carbohydrates. What you need to know.