Food & Nutrition

Ask the experts: carbohydrates and sugar

With the myriad of misinformation out there, it’s easy to get confused about how carbs and sugar can impact weight-loss and wellness efforts. Here Dr Michelle Celander, sets the record straight and shares her expert advice.
Published 27 May 2019

Are carbohydrates good or bad for you?

“There’s no such thing as good or bad foods. Carbohydrates are part of a healthy eating pattern and are an important source of iron and B vitamins, not to mention energy. Physiologically, they’re the main source of fuel for our brain, and they’re also key to our gut microbiome. While they are not ‘bad’, it’s crucial to remember that not all carbs were created equal. Dietary guidelines often refer to two kinds—refined carbohydrates (foods such as white bread and biscuits) and wholegrain carbohydrates (foods such as oats, barley and brown rice), with the latter having a higher nutritional value than the former. There is some emerging evidence that the balance of our gut microbiome can be influenced by our intake of carbohydrate types, and that excess sugar intake may create an imbalance of the good and bad bacteria in our gut. Enjoying a wide variety of fruit, vegetables and wholegrain foods can be key to a healthy microbiome. When making the choice to have carbs, it’s important to remember that those that fall into the wholegrain category are a key source of fibre and often the smarter option.”

Is a low-carb diet the best option for weight loss?

“As always, the best approach to weight loss is the one you can stick with long-term. Science tells us that there are lots of dietary approaches to losing weight, and that it is not necessary to cut out whole food groups like the carbohydrate food group, which would include bread and pasta. But thinking about the type of food you’re choosing—whether that’s carbohydrates or something else—and being mindful of the amount that you’re eating is important for weight management. If you’re looking to lose weight or follow a healthier eating pattern, it makes sense for refined carbohydrates to be one of the foods that you choose to eat less frequently. One reason is they’re low in nutrients, as much of the nutrition is lost in the refining process. They also have a higher glycaemic index (GI) than wholegrain carbohydrates, which means you wouldn’t be as satisfied after a refined grain food as you would be if you ate a wholegrain food.”

Should I limit my intake of carbs at certain times of the day, such as at night?

“There is no scientific proof that having foods at different times of day has a different physiological effect. Food is going to break down exactly the same way regardless of what time of day you have it. That said, there are lots of people that prefer to have their largest meal towards the beginning of the day, and a small meal at the end of the day, because they’re moving less and they sleep better. It’s really about finding that healthy eating pattern that you can stick with long-term. That will be the key to success, rather than any unrealistic rules, like ‘no carbs after five o’clock’, which is far too restrictive and essentially makes it unrealistic to sustain all the time.”

What’s the link between carbohydrates and sugars?

“The reason sugar and carbohydrates are a part of the same conversation is because sugar is a type of carbohydrate. In terms of refined versus wholegrain, sugar fits into that refined category.”

Are all sugars bad for you?

“We can think about sugar the same way as we think about other carbohydrates, which is that there are plenty of foods that contain sugar that are smarter choices, like fruit or yoghurt that have naturally occurring sugars in them. But there are other foods like chocolates, lollies and soft drinks, which are entirely refined. So following a healthier eating pattern would mean being mindful of the types of foods we eat that contain sugar.”

Why do I crave carbs and sugar and how can I stop it?

“When we look at the science, there is actually limited evidence that sugar is addictive. That said, a high intake of foods that have lots of sugar in them can contribute to us gaining weight and may have a negative impact on our body, such as our teeth. During winter, when we tend to lack exposure to sunlight, our bodies may experience a decrease in the production of serotonin, a hormone linked to mood, appetite and digestion. Eating some types of carbs helps in the production of serotonin, and therefore there is some thinking that there may be a link between us wanting to eat carbs and our bodies needing to top up serotonin. When it comes to why people crave sugar, it can often come back to the habits that we’ve created around particular emotions. So, for example, if we’re stressed or if we’re feeling unhappy, we’ve set up a habit loop where we say, ‘I’m feeling something,’ and then when we feel that, we may choose to eat something sweet, which is the behaviour, and the reward is that we feel better. To stop craving sugar you often need to break the habit loop. So when you’re feeling a certain emotion, instead of reaching for sugary foods replace it with a non-food behaviour that makes you feel good, such as going for a walk, taking a bath or listening to your favourite music.”