Carbohydrates - carbs - are an important source of energy for our bodies and form part of a healthy, varied and balanced diet. With the many confusing messages about carbohydrates, let’s simply go back to basics: What are carbs? What function do carbs have in our diet? And which foods contain them?

What are carbohydrates?

Carbohydrates are one of the three macronutrients found in our food - the others being fat and protein. Macronutrients are the nutrients we need in larger quantities and our main source of energy, as opposed to micronutrients which are mostly vitamins and minerals which we need in smaller amounts - but are equally important.

Carbohydrates exist in many forms, the most common being sugars, starches, and dietary fibres. In their most basic form, carbohydrates are made of building blocks of sugars and can be classified according to their molecular structure - how many sugar units they are made of. 

• Sugars - simple carbohydrates as they are in the most basic form. Sugars are often added to foods - free sugars - but are also found naturally in fruits, vegetables, and milk - naturally occurring sugars.

• Starches - complex carbohydrates made of lots of simple sugars linked together. Starches include bread, pasta, cereal, and certain vegetables - potatoes, peas, and corn.

• Dietary fibres - complex carbohydrates that our bodies cannot break down and are associated with many health benefits - feeling fuller for longer, normalising bowel movements & improving gut health. Fibre is found in many foods that come from plants. [find out more about Dietary Fibre]

What are the functions of carbohydrates?

First and foremost, the main function of carbohydrates is to provide energy to our bodies. Carbohydrates in food are broken down into glucose - simple sugar - which is then converted into energy used by our muscles, brain, organs and other cells to fuel and support our bodily functions and physical activity - moving or thinking. Our brains and red blood cells are particularly dependent on glucose as an energy source.

If our bodies do not need the energy immediately, the glucose is converted to glycogen - a stored form of glucose similar to starch - and stored in the muscles and liver, ready to be available when necessary. When our bodies do need energy - in between meals, during the night or for physical activity - the glycogen is converted back to glucose to be used as fuel and maintain our blood sugar levels. 

Unlike sugars and starches, dietary fibres cannot be broken down into glucose. They are either fermented by our gut bacteria or transit through the gut without being changed, which supports our digestion ensuring we have regular and normal bowel movement and a healthy gut environment.

How much carbohydrates?

Carbohydrates are an essential part of a healthy and balanced diet, but the amount of carbohydrates we should eat is not a one-size-fits-all. The amount we need varies depending on factors such as age, sex, health, and physical activity level. 

On average it is recommended that our total carbohydrate intake should range between 45% to 60% of our total energy intake. However it is also important to choose the most appropriate sources of carbohydrates by opting for starchy carbohydrates, fruits, vegetables, wholegrains or higher fibre varieties, and choosing less processed and high sugar foods - particularly ‘free sugars’. Starchy carbs and high-fibre foods are really important for our general health and wellbeing and we should be aiming to base our meals with these types of carbohydrates.

Generally speaking, a portion of carbohydrate-containing food is about the size of your fist or a handful.

What foods contain carbohydrates?

Carbohydrate-rich foods provide us with energy, as well as vitamins & minerals - B vitamins, iron, calcium, phosphorous, zinc - and fibre which are essential to our health. 

Carbohydrate-containing food include:

• Fruits - apples, bananas, berries, mangoes, melons, and oranges

• Starchy vegetables - potatoes, corn, and peas

• Grains - oats, cereals, rice, pasta, bread, noodles, and crackers.

• Pulses - dried beans, chickpeas, lentils, and peas

• Dairy products - milk and yogurt

• Snacks, sweets & juices - cakes, sweets, desserts, fruit juices & drinks, regular sodas, sports drinks, and energy drinks that contain sugar

Some foods do not contain a lot of carbohydrates, such as meat, fish, poultry, some types of cheese, nuts, and oils.

What’s the take-home?

1. ​​Carbohydrates are essential for providing fuel to our bodies for daily tasks - particularly our brain - and a range of nutrients to help us function optimally.

2. People have varying requirements for carbohydrates according to their lifestyle, weight, and activity level, so it’s important to choose the portions that suit our energy needs.

3. Foods containing carbohydrates are an important part of a healthy balanced diet and it is important to choose the appropriate sources of carbohydrates basing meals on starches and choosing wholegrain options - higher fibre - where possible, while limiting high sugar foods.

Check out these other Nutrition & Lifestyle posts…

References

1. European Commission. Health Promotion and Disease Prevention Knowledge Gateway. Dietary Fibre | Knowledge for policy. 2019. Retrieved February 4, 2022, from https://knowledge4policy.ec.europa.eu/health-promotion-knowledge-gateway/dietary-fibre_en 

2. European Food Safety Authority. Scientific opinion on dietary reference values for carbohydrates and dietary fibre. EFSA Journal. 2010; 8(3). https://doi.org/10.2903/j.efsa.2010.1462 

3. Stephen AM, Champ M, Cloran SJ, Fleith M, van Lieshout L, Mejborn H, Burley VJ. Dietary fibre in Europe: current state of knowledge on definitions, sources, recommendations, intakes and relationships to health. Nutrition Research Reviews. 2017, 1–42. doi:10.1017/s095442241700004x 

4. Barber TM, Kabisch S, Pfeiffer AFH, Weickert MO. The Health Benefits of Dietary Fibre. Nutrients. 2020;12(10):3209. Published 2020 Oct 21. doi:10.3390/nu12103209

5. Shortt C, Hasselwander O, Meynier A, Nauta A, Fernández EN, Putz P, Rowland I, Swann J, Türk J, Vermeiren J, Antoine J-M. Systematic review of the effects of the intestinal microbiota on selected nutrients and non-nutrients. European Journal of Nutrition. 2018, 57(1):25-49. doi:10.1007/s00394-017-1546-4 

6. European Comission. Food Safety - Nutrition Claims. Retrieved February 4, 2022, fromhttps://ec.europa.eu/food/safety/labelling-and-nutrition/nutrition-and-health-claims/nutrition-claims_en