Low-residue diet before colonoscopy

Low-residue diet before colonoscopy: day-by-day guide

The low-residue diet before a colonoscopy clears the bowel of seeds, fibres and residue so the laxative works as it should and the doctor gets a better view of the lining. Follow it properly and you reduce the risk of having to repeat the examination because the bowel was not clean enough.

These are the dietary rules from the Picoprep and Dulcolax instructions handed out at Kirurgen.dk in Charlottenlund. According to the clinic's plan you start a seed- and fibre-free diet 3 days before the examination. If your appointment letter or a specific message from the clinic says otherwise, the personal message applies.

Why a low-residue diet at all?

Whole seeds, nuts and insoluble fibre can lodge in the folds of the bowel or block the working channels of the scope. Even a small amount of fibrous stool can cover small polyps. The diet is not a health regimen but a short preparation that improves the view and thereby the doctor's chance of finding small changes.

Low-residue diet from 3 days before

Switch to easily digested food 3 days before the examination (the same day as the second dose of Dulcolax). You can still eat real meals, but avoid:

• wholegrain or seeded bread, muesli, rolled oats
• nuts, almonds, any seeds (sesame, linseed, chia, sunflower)
• coarsely grated raw fruit and vegetables with skin or seeds
• pulses (beans, lentils, chickpeas)
• popcorn, seeded crackers

You can eat:

• white bread, light rolls, plain crackers
• pasta, rice, peeled boiled potatoes
• lean meat, fish, eggs, soft cheese
• peeled, cooked or baked vegetables (carrot, courgette, potato)
• peeled apple, banana, stewed fruit, jam without seeds

Fluids in the days before

Same principles, and small frequent meals are fine. Drink plenty, especially from 2 days before. There is no single number of litres that suits everyone: if you have heart or kidney disease, a fluid restriction or diabetes, the amount and type of fluid must be agreed with the clinic or the doctor treating you.

The day before: last solid meal, then clear fluids

The day before, eat a small, light meal (for example a white roll with butter, or a piece of plain boiled chicken) no later than one hour before the preparation starts at 2 pm, that is by 1 pm. Until then you may eat low-residue food. From that point until the stop time stated in your appointment letter, clear fluids only. "Clear" means you can see through it.

Allowed:

• water, sparkling water
• clear squash, apple juice without pulp, light-coloured soft drinks, lemon water
• clear broth (chicken, vegetable), clear soup with no solids
• tea and coffee without milk
• water ice or sorbet without berries and fruit pieces

Not allowed:

• milk, cream, yoghurt, drinkable yogurt
• orange juice with pulp
• tomato or vegetable juice
• red, blue or purple drinks (blueberry juice, beetroot juice, red squash). The colour can look like blood in the bowel.
• alcohol in any form
• creamed soups and broth cubes with visible solids

Take the bowel prep according to the clinic's handed-out schedule: Dulcolax 2 tablets of 5 mg daily 4, 3 and 2 days before, and Picoprep the day before at 2 pm and 8 pm, each followed by at least 1.5 litres of clear fluid. See the details on the colonoscopy page and in the PDF. Do not use someone else's schedule, and do not change the dose or timing yourself.

Day of the procedure

No solid food. How long you may drink clear fluids on the day is stated in your appointment letter and depends among other things on your appointment time and any sedation. Always follow your current instructions rather than general figures. If you take regular medication, follow the individual plan agreed with the clinic or the doctor who prescribed it; anticoagulants and antiplatelet drugs, diabetes medication, insulin and GLP-1 agonists are assessed individually. Never stop or change prescribed medication without a specific agreement with the doctor treating you.

A practical overview

When	Food	Note
4 days before	Normal food	2 Dulcolax 5 mg, day 1 of 3
3 days before	Low-residue, no seeds or fibre	2 Dulcolax, day 2 of 3
2 days before	Low-residue, drink plenty	2 Dulcolax, day 3 of 3. Individual fluid amount in heart or kidney disease or diabetes
Day before, by 1 pm	Small, light meal	Light roll, boiled chicken or similar
Day before, 2 pm	Picoprep sachet 1 + at least 1.5 l clear fluid	Clear fluids only from here on
Day before, 8 pm	Picoprep sachet 2 + at least 1.5 l clear fluid	Stay close to a toilet
Day of the procedure	Clear fluids only	The stop time is in your appointment letter

Frequently asked questions

Can I drink coffee? Black coffee without milk counts as a clear fluid up to the stop time stated in your appointment letter. Milk or cream makes it cloudy and is not recommended.

What if I am hungry? A sweet clear fluid such as apple juice or clear squash gives a little energy. Clear broth also provides salt. If you have diabetes, the individual plan you have agreed with the clinic applies instead.

Can I chew gum? Follow the fasting instructions you have been given. If you are to have sedation, special rules may apply to chewing gum in the hours before the examination, so ask the clinic if it is not stated.

I have diabetes, what do I do? We take this into account in the individual plan. Call the clinic in good time so that we, together with the doctor who manages your diabetes treatment, can make an individual plan for food and medication around the bowel prep. Never stop or change prescribed medication without a specific agreement with the doctor treating you.

Ready for the procedure?

Read the full colonoscopy patient guide for what happens on the day of the examination, which side effects may occur, and how you get home afterwards.