10 signs you may not be eating enough fibre

Most adults in the UK struggle to meet their daily dietary requirements for plant-based roughage. According to official guidelines from the NHS dietary recommendations on fibre, adults should aim for 30g per day, yet the average intake sits at around 20g.

Knowing the 10 signs you may not be eating enough fibre can help you spot early warning signals from your gut, energy levels, and metabolism before they turn into long-term health issues.

Recognising a low fibre intake isn't just about digestion-it impacts everything from blood glucose regulation to heart health. If you are experiencing unexplained fatigue, digestive discomfort, or persistent hunger, your diet might be lacking this essential carbohydrate.

What is Dietary Fibre and Why Do You Need It?

Dietary fibre refers to the non-digestible carbohydrates found naturally in plant-based foods. Unlike simple sugars or proteins, fibre passes through the digestive tract largely intact, performing vital physiological tasks along the way. Fibre is categorised into two main types:

• Soluble fibre: Dissolves in water to form a gel-like substance. It slows down digestion, stabilising blood sugar levels and lowering LDL (cholesterol). You can find it in oats, barley, beans, lentils, apples, and psyllium. You can read more about managing cholesterol levels via the British Heart Foundation guidelines.

• Insoluble fibre: Does not dissolve in water. It adds bulk to stool and speeds up the movement of waste through the stomach and intestines. Excellent sources include whole wheat, wheat bran, nuts, seeds, and root vegetables.

Both forms work synergistically to nourish your gut microbiome, support regular bowel movements, and protect against chronic conditions such as type 2 diabetes and cardiovascular disease. To explore how your digestive system processes nutrients, visit our gut health and microbiome hub.

10 Signs You May Not Be Eating Enough Fibre

1. Irregular Bowel Movements and Constipation

Passing hard, dry stools or opening your bowels fewer than three times a week is a classic sign of low dietary fibre. Insoluble fibre attracts water and adds bulk to the stool, making it softer and easier to pass. Without sufficient roughage, transit time slows down significantly in the colon. For guidance on bowel habits, check the NICE guidance on constipation management.

2. Post-Meal Hunger and Frequent Craving Spikes

If you feel hungry shortly after eating a full meal, a lack of soluble fibre might be the culprit. Fibre slows gastric emptying, delaying the release of nutrients into your bloodstream and promoting satiety through fullness hormones like PYY and GLP-1.

3. Sluggishness and Post-Lunch Energy Crashes

Meals low in plant roughage and high in refined carbohydrates lead to rapid spikes and subsequent crashes in blood glucose. Soluble fibre slows carbohydrate absorption, helping maintain steady, sustainable energy levels throughout the day.

4. High Cholesterol Levels

Soluble fibre binds to cholesterol-rich bile acids in the digestive tract, carrying them out of the body through waste. When dietary intake is low, the body reabsorbs these bile acids, potentially leading to elevated circulating blood cholesterol.

5. Persistent Abdominal Bloating

While suddenly increasing fibre can cause temporary gas, a chronic lack of fibre leads to sluggish digestion and constipation, causing fermenting waste to build up in the colon and result in uncomfortable bloating. For more personalised advice, book a 1-to-1 appointment with our team.

6. Difficulty Managing Weight

Diets high in fibre-dense whole foods naturally lower energy density. High-fibre foods require more chewing, promote satiety, and reduce overall calorie intake without requiring strict portion restriction. If weight loss has stalled, evaluate your daily plant intake or book an initial appointment with our team.

7. Unstable Blood Sugar Spikes

Fibre acts as a natural buffer during digestion. Without adequate fibre to slow nutrient absorption, simple carbohydrates enter the bloodstream quickly, forcing the pancreas to secrete higher amounts of insulin. Over time, this contributes to insulin resistance. Check out the Diabetes UK guide to fibre and glycemic control for clinically validated advice.

8. Hard or Pelleted Stools

The consistency of your stool reflects your hydration and fibre intake. According to the Bristol Stool Chart, separate hard lumps (Type 1) or sausage-shaped but lumpy stools (Type 2) indicate that waste is spending too much time in the large intestine due to a lack of stool bulk.

9. Poor Skin Health and Breakouts

A sluggish gut can lead to reabsorption of toxins and metabolic waste products back into circulation. A healthy gut microbiome, supported by prebiotic fibres, helps reduce systemic inflammation that often manifests on the skin.

10. Low Mood and Brain Fog

Over 90% of the body's serotonin is produced in the gastrointestinal tract. Fibres act as prebiotics, feeding beneficial gut bacteria (Bifidobacteria and Lactobacilli) that produce short-chain fatty acids (SCFAs) like butyrate. These SCFAs communicate with the central nervous system via the gut-brain axis, influencing mood and cognitive performance.

How to Safely Increase Your Fibre Intake

Adding fibre to your diet should be done gradually to avoid uncomfortable gas, cramping, or bloating. It is recommended to gradually build up your fibre in small consistent amounts.

Practical Tips:

• Increase fluid intake alongside fibre: Fibre absorbs water to function correctly. Ensure you drink 1.5 to 2 litres of water daily to prevent intestinal blockage. Review the Association of UK Dietitians (BDA) fluid guidelines for detailed hydration targets.

  
  

• Keep the skins on fruits and vegetables: A significant proportion of insoluble fibre resides in the outer skin of potatoes, apples, pears, and carrots.

  
  

• Incorporate seeds: Sprinkle chia seeds, flaxseeds, or hemp seeds over porridge, yoghurt, or soups.

  
  

• Embrace plant diversity: Aim for 30 different plant foods per week, including fruits, vegetables, nuts, seeds, legumes, and whole grains.

Frequently Asked Questions

Can you eat too much fibre?

Yes, consuming over 45g–50g of fibre per day, especially if increased rapidly without sufficient water, can lead to intestinal gas, abdominal pain, bloating, and temporary nutrient malabsorption (such as calcium, iron, and zinc).

What is the difference between dietary fibre and prebiotic fibre?

All prebiotics are fibres, but not all fibres are prebiotics. Prebiotics (like inulin and galactooligosaccharides) are specific types of soluble fibre that selectively feed and stimulate the growth of beneficial gut bacteria in the colon.

Are fibre supplements as good as getting fibre from whole foods?

While supplements like psyllium husk or methylcellulose help manage bowel regularity, they lack the vitamins, minerals, antioxidants, and phytonutrient complexes found in whole plant foods. It is recommended to try a food-first approach whenever possible.

Take Control of Your Gut Health Today

Are you experiencing persistent energy crashes, bloating, or irregular digestion? Small changes to your daily diet can transform how you feel from the inside out.

Book a Consultation with our team today to receive a tailored, high-fibre meal plan designed for your lifestyle.