Low Residue Diet for Colonoscopy [ultimate guide]

When preparing for a colonoscopy, the low residue diet for colonoscopy is a crucial factor.

This specialized dietary approach ensures a clean and clear colon, which is essential for accurate examination results. 

This comprehensive guide will delve into the significance of the low residue diet for successful colonoscopy preparation.

We will cover the fundamentals of the low residue diet, including what it entails and why it is recommended for effective bowel prep.

Discover the types of foods to include and avoid, along with valuable practical tips and strategies to help you navigate this dietary adjustment smoothly.

What is the low residue diet for a colonoscopy?

The low residue diet for colonoscopy is a specialized dietary plan that minimizes undigested food residue in the gut.

Following this plan helps to create a clean and clear colon for the procedure, so your doctor can do a thorough examination. 

But what do we mean when we say ‘low residue’? There isn’t an accepted definition of residue, nor can we estimate the amount of residue in the gut (1). So, for the most part, when discussing a low residue diet, we focus on a low-fiber diet.

Fiber cannot be fully broken down and absorbed by the body. Instead, it passes through the digestive system relatively intact.

Adequate fiber intake is essential for maintaining a healthy digestive system, promoting satiety, and supporting overall health (2). 

Fiber-rich foods, such as fruits, vegetables, whole grains, legumes, and nuts, can contribute to the bulk and consistency of stool.

While generally beneficial for digestive health, it can leave residue in the colon, obstructing the view and potentially hiding polyps or other abnormalities. 

Low-fiber diets may reduce the size and number of your stools, which has been shown to cause less discomfort for patients compared to other historical methods of bowel prep (3, 4). 

Therefore, limiting fiber consumption for a specified period before the colonoscopy is recommended as it is the most tolerable and effective way to achieve optimal bowel cleansing and ensure accurate examination results.

How long before my colonoscopy do I start the low residue diet?

When you are booked in for a colonoscopy, you will be given instructions for when to start the low residue diet, among other elements of preparation.

Following the recommended timeline your healthcare provider gives for starting the low residue diet is crucial.

Dependent on your healthcare provider, you may start your low residue diet 1-3 days before your colonoscopy (5).

This gives your body enough time (along with the other elements of bowel prep) to achieve a clean colon for the procedure.

Foods to eat on the low residue diet for colonoscopy

You should avoid high-fiber foods on the low residue diet, such as whole grains, nuts and seeds. You will also have to remove the skin of fruit and vegetables and meats like chicken.

We have included a table below highlighting which foods are suitable for the low residue diet and which are not. However, please note that the guidance from your healthcare provider may vary slightly.

Foods to include and foods to avoid

	Foods to include	Foods to avoid
Protein sources: Meat, fish, eggs and alternatives	Lean proteins such as: Skinless chicken Lamb Beef Pork Turkey Offal (liver/kidney) Fish Eggs Tofu Quorn	Tough meat and gristle Lentils Chickpeas Beans of any variety (e.g. butter, borlotti, red kidney beans, baked beans)
Dairy	Milk Cheese Yoghurt or fromage frais Cream Butter or spreads Creme fraiche or sour cream	Yoghurt containing whole fruit, nuts or muesli Cheese containing fruit or nuts
Cereal	Cornflakes Rice cereals, e.g. rice krispies Strained porridge, e.g. Ready Brek	All Bran/bran flakes Weetabix Muesli Fruit & Fibre Porridge oats Shredded wheat Any cereal containing dried fruit or nuts
Bread	White bread Chapattis (if made with white flour) White pitta bread Poppadoms Garlic bread Cream crackers Rice cakes	Wholemeal bread Wholemeal crackers Seeded bread or crackers Wholemeal pitta bread Wholemeal wraps
Pasta and rice	White rice Any variety of white pasta or noodle	Brown rice Pearl Barley Quinoa Wholemeal pasta or noodles
Fruit	Peeled, stewed fruit Soft peeled fruit, e.g. plums, mangoes Smooth fruit juice Tinned peaches or pears Melon without seeds Bananas	Dried fruit (raisins, currants, prunes, apricots) Fruit with skin and pips Oranges and other citrus fruits Fruit juice or smoothies with bits
Vegetables	Well-cooked, peeled carrots, turnips/swede, butternut squash, marrow, pumpkin Well cooked broccoli or cauliflower (no stalk) Passata or tomato puree Potato without skin	Parsnip Salad vegetables: lettuce, cucumber, spring onion, whole tomatoes, peppers, raw spinach, celery Peas and sweetcorn Beansprouts Mushrooms Brussels sprouts Cabbage
Other	Plain biscuits e.g. Rich Tea, Nice or shortbread Plain scones Sugar, honey and syrup Seedless jam Smooth peanut butterIce cream / lollies / sorbetChocolateCrispsSauces – mayonnaise, tomato ketchup, BBQ sauce, smooth English mustard	Soup with chunks of vegetables Jam with pips/seeds crunchy peanut butter Sweets or chocolates with dried fruit or nuts Highly spiced foods e.g. chillies, curries Nuts and seeds PopcornCakes and biscuits made with wholemeal flour (e.g. digestive biscuits)Cakes and biscuits with dried fruit (e.g. fruit cake)

Tips for successfully following a low residue diet for colonoscopy

Transitioning to a low residue diet is often a challenge, particularly if you are accustomed to a high-fibre or diverse eating pattern. Here are some of our top tips to make it easier to stick to the diet.

1. Plan your meals before you start: Stocking up on low residue diet-friendly foods will make it easier to stick to the diet and relieve the stress of finding a suitable meal at the last minute.
2. Shop the perimeter of the supermarket. Here you’ll typically find fresh produce, lean proteins and dairy products. It might be a time-saver!
3. Read the labels on your food packaging: Pay attention to labels to ensure the products you pick up are low in fibre and don’t contain restricted ingredients. Avoid any items that list whole grains or seeds. 
4. Meal prep in advance: If you dedicate some time to meal-prepping dinners that adhere to the low residue diet, you will have easy access to them in the days running up to your colonoscopy.
5. Have snack options available: Keeping a variety of low residue diet-friendly snacks readily available can curb your hunger between meals while still sticking to the diet. Ideas for snacks are yogurts (no bits), rice cakes, and boiled eggs.
6. Communicate with your healthcare team with any questions or concerns.

Sample menu for low residue diet for colonoscopy prep

	Examples of low residue meals
Breakfast	Cornflakes with milk, White bread or toast with butter and/or honey, Scrambled/poached egg and white toast.
Lunch	Sandwich on white bread – cheese, ham, tuna, egg Jacket potato with cheese or tuna Cheese omelette
Dinner	Meat with mashed potato (no skin) and well-cooked broccoli and cauliflower Chicken with white rice Fish, potatoes (no skin) and boiled carrots Macaroni cheese Tuna pasta bake Tofu with rice and broccoli
Snacks	Yoghurt with no bits Hot chocolate / Horlicks Cheese and crackers Rice cakes Crisps Ice cream

This sample menu provides a general idea of the types of foods that you could include on a low residue diet.

FAQs about Low Residue Diet for Colonoscopy Prep

Can I have protein on a low residue diet?

Protein is allowed on a low residue diet. Some great options are lean cuts of meat, eggs, or firm tofu. However, you must avoid tough, fibrous cuts of meat or meat with gristle and skin. 

What can I expect when I go for my colonoscopy?

It can be daunting if you are unsure what to expect when you go for the colonoscopy procedure, but our blog post, ‘What to expect when you have a colonoscopy’, should give you some essential insight.

Can I take my medications as usual during the prep?

Most medications will be acceptable to continue taking during prep for your colonoscopy. You will usually be asked to stop any stool bulking agents (e.g. Fybogel) or antidiarrheal agents (e.g. imodium) beforehand. 

Some medications, such as the oral contraceptive pill, may be less effective after bowel prep, so your healthcare provider may recommend additional precautions.

You may also need to implement other measures if you take anticoagulation medications such as Warfarin.

If you take any medications, you should discuss this with your healthcare provider in advance so you have clear guidance regarding which medication regimens you need to alter, if any.

What happens after the colonoscopy

After your colonoscopy, you will have to reintroduce food gradually, but this won’t follow the low residue diet.

Your healthcare provider will give you specific instructions about what happens after your colonoscopy.

But if you want to get a headstart and know what to expect. In that case, you can read more about it in our blog: What to eat after a colonoscopy – Registered Dietitian advice

Summary

The low residue diet for colonoscopy prep is a short-term diet which intends to achieve optimal bowel cleansing.

It is a crucial factor in a successful colonoscopy procedure as it allows a clear passage for the camera. 

Remember to avoid high-fiber foods like whole grains, raw fruits and vegetables, nuts, seeds, and legumes and focus on low-residue alternatives.

Lean proteins such as skinless chicken and white carbohydrates are suitable options (e.g. pasta, bread or rice).

Now that you’ve researched a low residue diet for colonoscopy, you can prepare a menu and get a shopping list sorted to avoid any last-minute stresses!

If you are unsure about any aspect of the low residue diet for colonoscopy, or any other element of the procedure, reach out to your healthcare provider for more tailored advice.

Written by Annabelle Green, Registered Dietitian, reviewed by Kirsten Jackson, Consultant Dietitian BSc Hons, RD, PG Cert