Fibre, chewing, and the food that arrives whole

The human digestive system cannot break down cellulose — the enzyme for it simply is not there. That is true of everyone, colon or no colon: foods containing a lot of fibre pass through anyone’s intestines almost unchanged. With an ileostomy or a pouch you simply see the result.

Sweetcorn and beans are the foods most often passed whole. Nuts, coconut, some vegetables and some fruit are the ones that can cause a blockage — which may bring colicky pain that is usually temporary.

When it matters most

The effect is particularly noticeable if these foods are eaten on an empty stomach, when they will not be thoroughly mixed with other, less fibrous foods. The examples are pointedly ordinary:

• peanuts eaten by the handful before dinner
• celery
• unpeeled apples eaten as a snack between meals

Excesses of high-fibre items can also produce the opposite sensation to loose output: the stoma struggling to pass a semi-solid mass.

Two practical fixes

1. Chew high-fibre foods thoroughly before swallowing. It aids digestion and helps prevent flatulence, and it is the one tip that turns up in every set of guidance, for a stoma and a pouch alike.
2. Slit the kernels. Corn on the cob — often served as a first course, perhaps immediately after all those peanuts — is more easily digested if the kernels are slit with a knife before eating.

Two further details are reassuring rather than alarming. If a blockage occurs, your stoma may temporarily change in size or colour. And blockages are usually remedied easily, though they may require medical attention. The causes listed are a plug of food — nuts, citrus fruits, sweetcorn, coconut or other high fibre foods — something related to your surgery, or drugs, since some painkillers slow output down.

What changes with a pouch

For people with an ileoanal pouch the same foods turn up under a different heading. Coconut, spicy food, nuts, some fruit and food with pips are possible causes of anal irritation, and may also cause colicky pain, which is usually of a temporary nature.

And the general dietary point holds in both directions: some foods may simply be passed whole. Sweetcorn and beans again, and seeing them is not a sign that anything has gone wrong.

When low fibre is a deliberate choice

Most of the time the advice pushes towards a full and varied diet. There are two situations where it pushes the other way, and both are temporary.

• High output. A low fibre diet comes first among the ways to prevent output above 1.5 litres in 24 hours, alongside loperamide and 6–8 cups of suitable fluid a day.
• Bloating with a pouch. Some people find that a low residue diet minimises bloating while keeping the pouch working regularly. Increased frequency is most commonly linked to spicy food, and bloating to fibrous food.

There is a third, much smaller one: you may prefer a low-fibre meal before boarding a plane, to reduce the bulk of any bowel motion while in flight.