The Importance of Carbs, Fibre and Resistant Starch in Your Diet

The way that the body digests the food that we eat is really important and can play a crucial role in weight loss. Here are some of the key players in the diet when it comes to food digestion.


Carbohydrates: Friend or Foe?

Carbs are often seen as the bad guys in our diets. Instead of avoiding them completely, we need to understand which carbohydrates are good for us and why the speed of digestion is important. 

Carbohydrates are a mixture of starches, fibre and sugars. When carbohydrates are broken down in the body they are reduced to glucose (sugar) which is used for energy. The type of carbohydrate consumed will affect how quickly the food is digested and how quickly the glucose enters the bloodstream. 

It is important that we consume the right kind of carbs: the kind that the body digests slowly. Simple sugars, such as sugar, honey fruit and milk sugars, are absorbed by the body really quickly and they do not contain any vitamins, minerals or fibre. For this reason, they are called ‘empty calories’. Often, after eating food high in this type of sugar, the body has an initial energy burst and then falls into a slump. There are some types of natural sugars, such as those from fruit, which do contain other vitamins but are processed very quickly by the body. 

What we need are complex carbohydrates. To make sure that food is absorbed slowly, it is crucial to eat foods which are difficult for the body to digest, such as those high in fibre (wholegrain foods) and with complex structures that take a while to be broken down. Examples of these are white and brown rice and pasta, starchy vegetables like potatoes, and legumes. 

Complex carbohydrates release energy slowly so they are actually vital for getting us through the day. However, everything must be eaten in moderation. Eating too many carbs will cause weight gain, so be careful with your portion sizes. 

The Importance of Fibre

The digestion of carbohydrates can also be slowed by the consumption of fibre. Fibre helps us feel fuller for longer and it is important for our digestive health and regular bowel movements. Fibre gets rid of the build-up of unwanted toxins and improves the cholesterol and blood sugar levels. It reduces the risk of some diseases such as diabetes, heart disease and bowel cancer.

Although fibre is often overlooked in the diet, it plays a key role in our bodies internally as well as externally. By slowing down digestion, fibre helps with weight management. As an adult, you should be eating around 30g of fibre a day. This may seem like a lot, but it is possible! 

Soluble Fibre

Insoluble Fibre

  • Slows digestion.
  • It can be digested by your body and it dissolves in water. 
  • It may help reduce the amount of cholesterol in your blood.
  • Helps with constipation. Soluble fibres such as fruit and vegetables, oats and golden linseeds help soften your stools and make them easier to pass.
  • Sugar in carbs is released more slowly.
  • Cannot be digested and does not dissolve in water.  
  • Passes through your gut without being broken down and helps other foods move through your digestive system more easily. 
  • Keeps your bowels healthy and prevents digestive problems. 
  • If you have diarrhoea, you should limit the amount of insoluble fibre in your diet.

Both types of fibre leave you feeling full and can help with weight management

Fruit, such as bananas, apples and citrus fruits


Root vegetables, such as carrots and potatoes

Cereals, nuts and seeds (except golden linseeds)

Golden linseeds

Brown rice and pasta


Fruit and vegetables


Couscous and bulgur wheat

  • Add golden linseeds or fresh fruit to breakfast cereal or porridge
  • Use lentils in soups, vegetable curries or vegetable lasagne
  • Add beans to meals, such as casseroles and chilli
  • Add raw oats to cereal. Make ‘overnight’ oats
  • Use wholemeal bread and pasta instead of white. This includes using wholemeal flour when baking
  • Try to eat the skin on fruit and vegetables, such as apple skin, potato skin, and carrot. 
  • Make salads out of bulgur wheat and couscous

Here are a few examples of the amount of fibre in some common foods:

  • One bowl (30g) of high-fibre cereal, eg all bran  – 4g
  • One slice of wholemeal bread – 2 to 3g  (white bread is less than half this amount)
  • One small baked potato (with skin) – 3g
  • Half a tin of baked beans (200g) – 7g
  • A portion of dried figs (50g) – 4g
  • One medium-sized apple – 2g

When buying food make sure you check the labels. Foods that are classed as high fibre must contain at least 6g of fibre per 100g. If you are not used to including fibre in the diet, then add it gradually and increase your fluid intake.

Resistant Starch

Food containing resistant starch also serves to support the digestive system. Resistant starch functions as a prebiotic by supporting the beneficial bacteria in the gut and acts like a soluble fibre due to its water solubility and food indigestibility.

In the gut, resistant starch is broken into short-chain fatty acids that feed the good bacteria which keep us healthy and prevent diseases. They are able to lower the pH level in the digestive system and reduce inflammation. 

Resistant starch is a food that keeps us full for a long time and reduces our appetites, thereby aiding weight loss.  

There are different types of resistant starch, that can be found in:

  • Seeds, legumes and unprocessed whole grains
  • Green bananas, plantain, and raw potatoes
  • Starch-containing foods that have been cooked and cooled, such as rice, pasta, and defrosted bread. 

You might notice that some of these foods were mentioned above because they contain fibre. Try to cook with these foods more often for the variety of benefits that they bestow on our digestive systems and the body’s process of breaking down carbohydrates, which in turn helps us lose weight.

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