Can you ‘overmaxx’? The truth about how much fibre you REALLY need

A wellness trend popularised by social media, ‘fibremaxxing’ is all about upping your fibre intake; this might involve adding fibre-rich foods like prunes to your diet or, when taken to extremes, boosting fibre through supplements such as powders.

Most of us think of fibre as the non-digestible mainly carbohydrate material found in plants – the part that our digestive enzymes can’t break down. Getting enough of this fibre is associated with a lower risk of heart disease, stroke, type-2 diabetes and colon cancer. Plus, when you eat fibre-rich foods, they’ll keep you fuller for longer, improve your digestion and keep you regular. When eaten as part of your everyday diet, fibre supports gut health and may increase the number and variety of gut bugs that live there; it also helps us maintain a healthy weight, supports cholesterol balance and regulates hormones.

Is all fibre the same?

The answer is no – there are three main types of fibre:

• Soluble fibre thickens and becomes gel-like when mixed with fluid. Examples include gums, pectin, beta-glucans in oats and the fibre found in psyllium husks. If you’re a keen jam maker, you’ll be familiar with this, because the soluble fibre pectin is key to getting a good ‘set’. In our bodies, these fibres slow our digestion and the speed at which we absorb nutrients. Be aware, though, that soluble fibre may affect the absorption of prescribed medication, so refer to your GP if needed
• Insoluble fibre is what we tend to refer to as ‘roughage’; this isn’t changed by our digestion, so it acts as a bulking agent that helps prevent constipation. Eating high levels of this type of fibre throughout our lifetime may help lower our risk of developing conditions like haemorrhoids, as well diverticulitis
• Fermentable types of fibre are broken down by gut bacteria; these fibres act as a fuel source for the gut bugs and, in return, create beneficial by-products called short-chain fatty acids (SCFA). These SCFAs feed the cells of our colon, help make our immune system more robust, improve our tolerance to certain foods and regulate our allergy response. Resistant starch, as you might expect, is resistant to our digestion but is fermentable, so it gets broken down by bacteria. Studies suggest that when we include foods rich in resistant starch, we benefit from better blood sugar levels, improved appetite control and more efficient digestion

Discover our full range of health benefit guides, including our spotlight on high-fibre diets and our top high-fibre recipes, including kidney bean curry and chickpea burgers.

No, extra fibre is not necessarily safe for everyone – it depends on your personal circumstances. For example, if you’ve recently been diagnosed with diverticulitis, you should follow a low-fibre diet until your condition is under control. Similarly, if you have irritable bowel syndrome, you may find your tolerance to fermentable fibre is low and you should minimise these in your diet until your condition is more manageable. Examples of these include inulin found in asparagus, onions and artichokes, and oligo-fructose found in bread, cereals, ripe bananas and some vegetables.

Speak to your GP or a registered dietician for further advice – they may suggest you follow a low-FODMAP diet under their professional supervision.

Anyone on prescribed medication should use caution when adding significant amounts of additional fibre to their diet, because certain types like pectin (fruit) and beta-glucans (oats) may affect the body’s ability to absorb these medications, including aspirin. Likewise, if you’re on insulin to control diabetes, you should be aware that fibre may reduce your blood sugar levels, which may mean you need an adjustment to your medication. Always speak with your GP first.

How much fibre should I be eating each day?

As part of a balanced, healthy diet, UK guidelines recommend an average adult consumes 30g fibre per day. Most of us fall short of this amount. Good sources include fresh and dried fruit, vegetables, beans and pulses, nuts, seeds and wholegrain cereals.

Children, depending on their age, should be eating between 15-25g fibre per day.

Symptoms of too much fibre

If you increase your fibre intake too quickly, you may experience uncomfortable side effects, such as:

• bloating
• cramping and wind
• constipation
• diarrhoea

These are all signs that your system is overwhelmed. High fibre levels may impact your appetite, making you less likely to eat foods rich in other essential nutrients like protein and fats. If you’re a keen exerciser, you may not take on enough calories to fuel your sport. In extreme cases – and when not enough liquid is consumed – a very high-fibre diet may lead to bowel blockages.

If you’ve been diagnosed with a gut condition such as irritable bowel disease, irritable bowel syndrome or Crohn’s disease, additional fibre is likely to aggravate your symptoms.

Symptoms of too little fibre

Telltale signs you’re not getting enough include:

• getting hungry soon after eating
• experiencing blood sugar swings and feeling sluggish after a meal
• having cholesterol levels higher than recommended
• being overweight
• experiencing hormonal swings
• getting constipated and suffering from haemorrhoids

Over time, low levels of dietary fibre may lead to gut conditions like diverticulitis or bowel cancer.

How to safely introduce more fibre into your diet

If you’re looking to increase the fibre in your diet, be sure to drink extra fluids to help the fibre do its job properly, and make changes to your diet over a period of weeks rather than days – this will allow time for your body to adjust. As you gradually increase your fibre intake, your digestive system and gut bacteria should adapt and the uncomfortable digestive symptoms will subside.

If you are taking prescription medication or have been diagnosed with a gut condition such as diverticulitis or IBS, you should refer to your GP or a registered dietician for guidance.

Found this useful? Now read:

High-fibre breakfast recipes
Gut health: what does it really mean?
10 probiotic foods to support your gut health
How to improve your digestion: Healthy Diet Plan
Top 10 anti-inflammatory foods

Have you tried fibremaxxing? What foods have you included? Share your experiences in the comments below.

This page was reviewed on 3 October 2025 by Kerry Torrens.

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