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What are carbohydrates? Everything you need to know

Carbohydrates are an important source of energy, supplying between 40-70% of energy intake in most countries worldwide. In fact, carbohydrates are the main source of energy in your diet, and it’s where over half of our fuel source should come from are broken down by our digestive systems into glucose. This provides us with the energy our brains and bodies need to function, and are its preferred source of energy. You can find them in a broad range of both healthy and unhealthy foods including pasta, rice, bread, biscuits, soft drinks, fruits and vegetables. What impact they have on your health will vary enormously depending on which types you choose.

With this in mind, let’s take a look at how to get the right balance when it comes to your carbohydrate intake.

There are two types of carbohydrates – complex and simple. Let’s break each one down.

What are complex carbohydrates?

Complex carbs provide more sustained energy as they release it slowly over time, and can be found in many vegetables and legumes. Complex carbohydrates are often high in fibre and packed with vitamins and minerals. This type of carbohydrate is harder to break down and foods such as brown rice and oatmeal don’t turn into fat as easily as simple carbohydrates – which are found in fizzy drinks, crisps and chocolate. It’s therefore better to opt for complex carbohydrates that help us hit the recommended amount of fibre which, according to BANT (British Association for Nutrition and Lifestyle Medicine) is 30 grams per day for an adult.

What are simple carbohydrates?

Simple carbohydrates are foods that break down quickly to be used as energy. They can be found naturally – such as in fruits and milk – or in refined sugars and processed foods, such as sweets, cakes, biscuits and soft drinks. 

For a more healthy and balanced diet, focus on complex carbohydrates rather than simple.

What’s the difference between simple and complex carbohydrates?

Simple carbohydrates can cause spikes in blood sugar – those spurts of energy you feel after eating something sweet – whereas complex carbs release their energy more slowly. Not all simple carbs are equal, however; fruits, for example, have more nutritional benefit but should be eaten as part of a balanced meal with fat and protein. Complex carbohydrates also contain more vitamins, minerals and fibre.

What are starches?

Starchy carbohydrates in jars including white pasta rice, grains and cereal products.

Starchy foods are complex carbohydrates and provide more sustained energy as they take longer for your body to digest;  they’re a key part of a healthy and balanced diet. 

Some examples of starchy foods include:

  • Starchy vegetables – beetroot, parsnips, potatoes, squash, sweet potatoes and sweetcorn
  • Grains
  • Lentils
  • Potatoes
  • Bread, especially wholemeal
  • Pasta
  • Rice 
  • Cereal products

Starchy foods are not only a good source of energy but they provide us with vitamins, minerals and fibre.

What is fibre?

Different food sources of fibre including bananas, green leafy veg, broccoli, beans and nuts.

Fibre is a complex carbohydrate found in plant foods such as fruits, vegetables, grains and legumes. Broadly speaking there are two types of dietary fibre: soluble and insoluble. Soluble fibre forms a gel like substance in the gut which can help lower cholesterol. Insoluble fibre mostly passes through the digestive system undigested but has a beneficial effect on stool movements and bowel health. Most foods contain both soluble and insoluble fibre.

Some examples of fibre rich foods include:

  • Vegetables such as carrots, broccoli, kale, peas and sweetcorn
  • Fruits such as pears, raspberries, kiwi and oranges
  • Legumes such as peas, beans and lentils
  • Seeds and nuts (raw and unsalted)
  • Wholegrains such as oats, spelt and rye
  • Potatoes with their skin on

When grains are refined, the refining process removes the outer husk which contains most of the fibre. There are higher concentrations of nutrients and chemicals from plants (also known as phytochemicals) in the outer part of the grain so eating refined carbohydrates will also result in reduced nutrient intake.

Switching from refined bread, flour, pasta and rice to whole grain versions is a simple way to boost your fibre content. If in doubt as to whether it has been refined the clue is usually in the colour. White usually equals refined. Unrefined products tend to be browner.

Although most of us don’t eat enough fibre, it’s essential for keeping your body healthy, and ensuring that the digestive system works as it should. In the Western world, most of us should increase our dietary fibre intake by around 50% from our current levels with the NHS advising that we aim for over 30g of dietary fibre daily. A healthy gut microbiome also needs dietary fibre to thrive. You can find out about how much fibre you’re getting from food labels, but a daily intake might include a breakfast of porridge plus fruit and nuts; lunch including raw veg and hummus; dinner of meat with 3 crunchy cooked veg.

What is sugar?

Sugars are a type of simple carbohydrate. They can be found naturally – such as in honey, fruits and milk – but they can also be found in refined sugars and processed foods, such as sweets, cakes, biscuits, pastries and soft drinks. Not only are these types of refined and processed foods bad for your blood sugar but they also have little to recommend them in terms of fibre, vitamins and mineral content.

Most people are aware that foods like sweets, fizzy drinks, biscuits and ice cream are high in added sugar but many are unaware that processed foods like ready meals, pasta sauces, salad dressings and even yoghurt – usually low fat – can be high in added sugar.

How are carbohydrates digested?

The digestion process actually begins before you even pop food in your mouth! Seeing and smelling (and even talking about) food can trigger the release of gastric acid in the stomach, which gets your digestive system ready for the incoming meal. It also induces enzyme and saliva production, which breaks down the food as you chew. The next stages of the digestion process take place in the stomach, the pancreas and the small intestine, which breaks down carbs into glucose. This is then absorbed into the bloodstream and can be used as energy or stored as fat by your body.

For more information on this key process, head over to our previous article on how to improve your digestion.

What is the recommended daily amount (RDA) of carbohydrates?

According to the NHS, we should be consuming at least 260 grams of carbohydrates a day. The BANT Wellbeing Guidelines recommends that 50% of our food intake should come from carbohydrates. 

However, as we have discussed, carbohydrates are not all equal in terms of their health impact. It’s interesting to note that the Japanese residents of Okinawa have some of the highest numbers of centenarians anywhere in the world and obtain over 85% of their caloric intake from carbohydrates. Their carbohydrate intake is largely made up of orange-yellow root vegetables such as sweet potatoes and a wide range of green leafy vegetables. These are nutrient dense, rich in beneficial plant chemicals and quite unlike many of the processed carbohydrates that we would see in a typical Western diet. So, try to ensure that your carbohydrates are coming from a wide range of healthy foods rich in vitamins, minerals, phytonutrients and fibre.

What are the benefits of carbohydrates?

  • Providing energy First and foremost, carbohydrates provide us with energy, as we’ve covered earlier in this piece.
  • Providing fibre Dietary fibre intake has been associated with many health benefits including a healthy gut microbiome, favourable body weight, overall metabolic health, colonic health and lower risk of cardiovascular disease and bowel cancer. There is some evidence to suggest that people who eat higher levels of dietary fibre and wholegrains have lower rates of non-communicable diseases compared with people who eat a lesser amount. A study by The Lancet suggested a 15 – 30% decrease in all-cause and cardiovascular related mortality when comparing people who eat the highest amount of fibre to those who eat the least. The study also found that eating fibre-rich foods reduced incidence of coronary heart disease, stroke, type 2 diabetes and colorectal cancer by 16-24%.
  • Providing phytochemicals – Plant based foods such as fruits, vegetables and grains are our main source of dietary phytochemicals. Phytochemical intake is linked with protection from many chronic diseases. Research is ongoing.

The breakdown of carbohydrates

There are many factors that affect how efficiently your body breaks down carbohydrates. If you have a slow metabolism, this could mean that you put on weight more easily.

Understanding your genetic predisposition to metabolise carbohydrates may help you make food choices that work better for you.

Evergreen Life can help you understand your carbohydrate metabolism through home genetic testing kits. The DNA test results provide insights and recommendations into key areas of your health and wellbeing like diet and metabolism, helping you to make more informed decisions about the food you eat.

Are you eating the right way?

The right type of carbohydrates have many health benefits and are an important part of a healthy, balanced diet. Whilst all this can seem overwhelming, if you focus on getting the majority of your carbohydrates from a diverse range of unprocessed wholegrains, beans, lentils and colourful vegetables and fruits then you’ll be on the right track. All of these come with a whole host of other health benefits including vitamins, minerals, fibre and beneficial plant chemicals. The balanced plate from BANT is great guidance for making sure your plate has a bit of everything.

So, what score would you give your food and nutrition? Could you improve it? Our app helps you to discover your Wellness Score and puts you in charge of becoming your own wellness expert with helpful articles like this one on what’s in a healthy diet.

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Be as well as you can be? Download the Evergreen Life app today and get started on your wellness journey.

Reviewed by:

Dr Brian Fisher MBBCh MBE MSc FRSA – Medical Expert

Anna Keeble – Head of Content

  1. Bridges M (2022) Simple carbohydrates. MedlinePlus.
  2. British Nutrition Foundation (n.d.) Fibre. British Nutrition Foundation. 
  3. Jéquier E (1994) Carbohydrates as a source of energy. Am J Clin Nutr. 59: 682S–685S (doi: 10.1093/ajcn/59.3.682S).
  4. Mayo Clinic (2022) Carbohydrates: How carbs fit into a healthy diet. Mayo Clinic.
  5. NHS UK (2022) Food labels. NHS UK. 
  6. NHS UK (2022) How to get more fibre into your diet. NHS UK. 
  7. NHS UK (2020) Starchy foods and carbohydrates. NHS UK. 
  8. Science Daily (2019) High intake of dietary fiber and whole grains associated with reduced risk of non-communicable diseases. Science Daily. 
  9. Scientific Advisory Committee on Nutrition (2015) Carbohydrates and Health. Scientific Advisory Committee on Nutrition. 
  10. Tufts Now (2008) Low-carb diets can affect dieters’ cognition skills. Tufts Now.
Picture of Ingrid Kitzing

Ingrid Kitzing

Ingrid Kitzing is a nutrition expert here at Evergreen Life. She trained as a Nutritional Therapist at The College of Naturopathic Medicine, and is passionate about helping people bring healthy and nutritious food into their lives.