Why you need more fiber in your diet

Findings from the latest National Diet and Nutrition Survey (NDNS) published this week have shown that fiber intake is way below the recommended guidance of 30g per day.

Most adults are getting around 19g per day with older adults over 65 managing to get around 17.5g per day. 

Teenagers have the lowest fiber intake, with most barely managing to eat more than 15g per day. That is only half of what is recommended – and girls fare worse than boys by eating little more than 14g per day.

These findings come as no surprise when you delve deeper into the survey to look at what people are eating

The biggest contributors to fiber intake in adults are cereals and cereal products (38 percent). Most choose refined carbohydrate foods such as white pasta, bread and rice in favor of wholegrain varieties – a small switch that drastically affects their intake. Few people regularly eat nuts and seeds a rich source of fiber – despite the rising trends in these foods. 

What’s more, only 27 percent of adults and eight percent of children are managing to eat the recommended five daily servings of fruit and vegetables with the majority barely reaching four.

Here, Rob Hobson, Healthspan Head of Nutrition and a registered nutritionist, analyzes the dismal figures and explains how we could all squeeze a bit more fiber into our diets to transform metabolism, heart health, and weight management – among other things.

Despite the healthy eating ‘trend’, fiber intake remains low, new figures show. Rob Hobson, Healthspan Head of Nutrition and a Registered Nutritionist, explains how to combat the issue

What are the benefits of eating more fiber?

Dietary fiber may not be the most exciting of topics in the world of nutrition but it has been shown over and again that a diet rich in fiber is hugely beneficial to your health.

A large review of 27 studies published in the American Journal of Epidemiology concluded that higher dietary fiber intake was associated with a lower risk of death including cardiovascular disease, diabetes and cancer.

Dietary fiber helps to maintain good heart health by reducing levels of cholesterol in the blood, which is considered to be a risk factor for heart disease.

Inflammation also contributes to disease and research has shown how dietary fiber may have a role to play in modulating the immune system and so reducing disease risk.

There is good evidence to show that a diet high in fiber may help to prevent Type 2 diabetes.

For those with the condition, eating a diet rich in fiber can help to balance blood sugar levels. Fiber also helps to bulk out the diet and promote fullness that may help with weight loss, which can help with the condition.

Certain fiber also help the bacteria in your gut to flourish, which has many benefits to health that are linked to your microbiota.

Foods rich in compounds called lignins and oligosaccharides (found in bananas, Jerusalem artichokes, onions, garlic and oats) have been shown to act as a prebiotic in the gut which help to ‘feed’ gut bacteria.

The World Cancer Research Fund (WCRF) has estimated that 45 percent of bowel cancer could be prevented through diet, physical activity and weight.

The most up to date information regarding bowel cancer showed that there was convincing evidence that food containing dietary fiber decreased your risk of developing the disease.

What is fiber?

Dietary fiber is used to describe plant-based carbohydrates that are not able to be digested in the small intestine so make their way to the large intestine or colon.

This also includes other plant components such as lignins and oligosaccharides. The main role of dietary fiber is to maintain a healthy digestive system.

Fiber is classified into two groups called soluble and insoluble they usually both occur in fiber-rich foods.

Foods high in soluble fibers include oats, barley, rye, beans, lentil, bananas, pears, apple, carrots, potatoes and golden linseeds.

They are made from the parts of plants that absorb water such as cell walls and gums that hydrate your intestines making stools soft, which can be beneficial when suffering with constipation.

Foods high in insoluble fiber include wheat bran, dried fruit, corn, wholegrain cereals, wholegrain bread, nuts and seeds.

This type of fiber is often referred to as roughage, which passes through the gut without being broken down and helps with digestive transit by providing bulk and stool size.

What are the best sources of fiber?

This table is just to illustrate foods that are a rich source of fiber:

  • Oat bran 12g
  • Black beans 12g
  • All bran breakfast cereal 10g
  • Lentils (cooked) 10g
  • Adzuki beans (cooked) 8g
  • Red kidney beans (cooked) 8g
  • Pearl barley (cooked) 6g
  • Quinoa (cooked) 5g
  • Oats 5g
  • Wholemeal spaghetti (cooked) 5.5g
  • Brown rice 4.5g
  • Aubergine 4g
  • Brussels sprouts 4g
  • Linseeds 4g
  • Raspberries 3g
  • Granary bread 3g
  • Dried figs 3g
  • Almonds 2.5g

Getting started: 9 ways to begin sneaking fiber into your diet

1. Small steps

Start by making small changes to the way you currently eat. Choose to eat more fruit and vegetables and switch to wholemeal varieties of starchy foods like pasta, rice, bread and breakfast cereals.

2. Squeeze it in-between

Opt for healthy snacks such as those made with dried fruit and nuts.

3. Look at your sides

Try to include a serving of beans, pulses or lentils into your daily diet, which can be used to make dips or added to soups, salads and one-pan meals.

4. Embrace skin

Leave the skin on your fruits and vegetables to increase the fiber content. Same goes for potatoes especially sweet potatoes

5. Drink it

Add oats, nuts and seeds to smoothies – and use the WHOLE fruit

6. Sprinkle it over dinner

Top your salads, curries, stews and more with nuts and seeds

7. Pop it on your breakfast

Used dried fruit and oat granola to top yogurt or fresh fruit salad

8. Check the labels

Try to opt for products that have the word ‘whole’ in e.g. whole grain

9. Hydrate!

Remember to drink plenty of water

Put it into action: A one-day meal plan which adds up to 30g fiber


  • Two slices of wholemeal bread toasted (6g) with sliced avocado (3.4g)
  • Small glass of fruit smoothie (1.5g)


  • Grain and lentil based chicken salad (10g)
  • Banana (1.1g)


  • Quorn chilli with wholegrain rice (10g)
  • Fresh berries and sunflower seeds (2.5g)

Total fiber: 34.5g

Can you eat too MUCH fiber?

Increasing your intake of fiber suddenly may cause bloating and wind but this will soon pass once your body has got used to it.

People suffering with IBS may need to be careful about the amount of fiber they eat as this can irritate the gut.

Many high-fiber foods (nuts, seeds, grains and beans) contain compounds called phytates, which can bind with minerals such as calcium, zinc and iron preventing their absorption.

If you are getting a good supply of minerals from your diet then this is not such an issue but for some, this may not be the case so it may be worth considering looking at supplement the diet with a good quality multivitamin and mineral if you have very low levels such is the case with iron deficient anemia then it may be more of a concern.

There’s no doubt that fiber is important for health with the benefits reaching beyond just digestive health.

Most people don’t get enough fiber and making simple changes to your current diet such as eating more fruit and vegetables and switching to whole grains varieties of starchy foods is a good place to start.

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