There is a lot of confusion about carbohydrates and their effect on our health, especially surrounding their consumption and subsequent effect on weight loss, body fat and a person’s risk of developing heart disease.
So here is what we really know about carbohydrates, and how they can be incorporated into a healthy diet.
What is a carbohydrate?
Carbohydrates are one of three large energy-yielding nutrients known as macronutrients. The other two are fats and proteins. Carbohydrates are a large family of different carbon-oxygen-hydrogen based chemicals that are found in foods that the body can consume, break down, absorb and metabolise for energy. In fact, carbohydrates are the body’s primary source of energy – the body will prioritise burning carbohydrate first (over fats and proteins) if it’s available.
When a nutritionist talks about carbohydrates, he or she is talking about three main sub-groups of nutrients: sugars, starches and fibres. These three are all naturally occurring nutrients that originate in plant-based foods.
It’s important to remember that unless we’re eating a processed food, such as a lolly or soft drink, we rarely eat carbohydrates in isolation. Food is more often than not a mixture of different nutrients. The combination of nutrients in the whole food is what we use to create a healthy eating pattern, not the individual nutrients themselves.
Does the body need them?
Carbohydrates are the primary energy source of the body – the brain relies on carbohydrates to function, and during movement (particularly moderate to high intensity movement) the muscles are carbohydrate-burning machines.
We have also known for a long time of the benefits of plant-based diets, which are rich in whole foods, particularly fruits, vegetables, whole grains, legumes, nuts and seeds. All these foods are rich in carbohydrate, in varying amounts. In particular, they are good sources of fibre, vitamins, minerals and other health-promoting chemicals known as phytonutrients.
Fibre in particular is vital for long-term gut health, reducing cholesterol reabsorption and indirectly helping individuals manage a healthy weight and reduce their risk of developing heart disease. There is also great benefit from the vitamins and minerals that these foods also add to our diets.
The body can function without carbohydrates. This metabolic adaption is called ketosis and occurs when there are extremely low amounts of carbohydrate in the diet for an extended period of time. The long-term effects of ketosis are unknown. I would argue that in order to achieve and maintain ketosis (a state that may not be healthy long term), you would need to cut carbohydrate intake to the point where you wouldn’t be able to meet your daily fibre and vegetable requirements, two things we know are vital for long-term health.
How do we eat them healthily?
Knowing that carbohydrates are important for long-term health is all well and good, but plenty of carbohydrate-rich foods aren’t healthy. In addition, the environment we live in means many people have sedentary, inactive lifestyles, and we’re surrounded by processed, high-energy, low-nutrient foods. Choosing which foods to eat isn’t as simple as it used to be. This is why it’s important to think about the quality and quantity of carbohydrate-rich foods that you consume each day.
As mentioned earlier, fruits, vegetables, whole grains, legumes, nuts and seeds are all carbohydrate-rich foods and also contain many other nutrients. It’s these whole foods that you want to build your diet out of first. When we choose a whole food, not only do we eat carbohydrate in a more appropriate amount, but we also get the whole combination of nutrients that the food contains. It’s this combination, delivered to the body as a whole food, that promotes health in our bodies.
Because we spend a good deal of our days sitting and not being active, even when we’re choosing whole foods we can still consume more energy than our body needs. In fact, the overconsumption of carbohydrate in excess of the body’s needs is where we fall into ill health. Excess carbohydrate intake places a large metabolic load on the body. When the body constantly has high levels of blood sugars (the end point of food sugar and starch) to deal with over time, this leads to weight gain, poor metabolic health and an increased risk of heart disease.
Understanding a healthy portion size that’s right for you is a really important part of the process. Everybody has slightly different energy and carbohydrate needs. Advice from a qualified nutrition professional will come in very handy at this point. A trained professional will take into account your goals, your metabolic health, your activity levels and your food preferences before making recommendations. They shouldn’t give you a one-size-fits-all approach – if they do, please seek a second opinion.
A good place to start is to fill ¼ of your dinner plate with carbohydrate-rich foods like brown rice, sweet potato, quinoa, rolled oats, wholemeal pasta, grainy bread, lentils, chick peas or corn on the cob. Fill the rest of your plate with vegetables and protein-rich foods. Then tweak it up or down depending on your energy levels, appetite and goals.
About the author
Kate Freeman is HRI's resident nutritionist. She is a registered nutritionist from Canberra, Australia and the creator and managing director of the largest private nutrition practice in Canberra, The Healthy Eating Hub. Kate consults, writes, presents and mentors in the field of nutrition and has over 10 years of experience in the industry.