Fibre: the nutrient most people miss

Soluble and insoluble fibre

You will often see fibre split into two types. Most plant foods contain both, so you do not need to track them separately, but it helps to know what each does.

• Soluble fibre dissolves in water to form a gel. It slows digestion and can help lower LDL cholesterol and steady blood sugar. Good sources: oats, barley, beans, lentils, apples, citrus fruit and linseed.
• Insoluble fibre does not dissolve. It adds bulk and helps food move through the gut. Good sources: wholemeal bread, wholewheat pasta, brown rice, bran, nuts, seeds and the skins of fruit and vegetables.

Some types of fibre, including resistant starch found in cooled potatoes, rice and slightly green bananas, act as food for gut bacteria. That links fibre closely with gut health.

What 30 g a day looks like

Thirty grams sounds abstract until you see it on a plate. Here is a normal day that gets there without any special fibre products. Figures are approximate.

• Breakfast: porridge made with 50 g oats, topped with a handful of raspberries and a spoon of ground linseed. About 10 g.
• Lunch: two slices of wholemeal bread with chicken, salad and a piece of fruit. About 7 g.
• Snack: a small handful of almonds and an apple with its skin. About 5 g.
• Dinner: chilli made with kidney beans, served with brown rice and a side of broccoli. About 12 g.
• Total: roughly 30 to 35 g

Compare that with a typical day of white toast, a meal deal with a white bread sandwich and crisps, and a takeaway pizza, which may come in at well under half. The difference is not dramatic changes, just a series of small swaps.

Easy swaps that add up

The easiest way to raise fibre is to change what is already on your shopping list rather than adding new meals.

• White bread to wholemeal or seeded bread
• Sugary cereal to porridge, bran flakes or wholegrain wheat biscuits
• White rice and pasta to brown rice and wholewheat pasta, or a half and half mix
• Peeled potatoes to potatoes with skins
• Half the mince in a bolognese or chilli to lentils or beans
• Crisps to popcorn, fruit or a small handful of nuts
• Fruit juice to whole fruit

On food labels, a product can be called a 'source of fibre' with at least 3 g per 100 g and 'high fibre' with at least 6 g per 100 g. That is a quick way to compare breads and cereals. Our guide to reading UK food labels explains the rest of the panel.

Go slowly and drink more

Jumping from 15 g to 35 g of fibre overnight is a common mistake. Your gut bacteria need time to adapt, and a sudden increase often brings wind, bloating and discomfort. Add one swap every few days and build up over two to four weeks.

Fibre holds water, so drink more fluid as you increase it, or you risk constipation rather than solving it. Being active helps too. Regular movement, including your normal training, keeps the gut moving.

If you have irritable bowel syndrome, coeliac disease, inflammatory bowel disease or you have been given specific dietary advice, follow that advice and speak to your GP or a registered dietitian before making big changes. Some high-fibre foods trigger symptoms in people with IBS, and the right approach is individual.

Fibre around training

Fibre is great for health but slow to digest. A big bowl of bran cereal, lentils or beans in the hour or two before a hard session can mean stitches, cramps or an urgent search for the toilet, especially with running or jumping.

The fix is timing, not avoidance. Eat most of your fibre at meals well away from training and choose lower fibre carbohydrates such as white toast, a bagel or a banana close to the session. After training, go back to normal. If you train at the Monday 6pm Full Body class at Lycan Strength, a bean-heavy lunch is fine, but make your pre-training snack a lighter one. Our guide on what to eat before a workout goes through the timings.

See your GP if you notice a change in your usual bowel habit that lasts three weeks or more, blood in your poo, unexplained weight loss or ongoing tummy pain. These are not caused by eating more fibre and need checking.