A doctor may recommend a low residue diet for a few reasons, including a flare-up of ulcerative colitis (UC). But it isn’t right for everyone with UC and isn’t meant as a long-term solution.

A low residue diet can help limit food waste and clear the colon, giving it time to rest and heal. It’s not a cure for UC or other gastrointestinal conditions. But it can help manage abdominal pain and other symptoms during a flare-up.

Staying on this diet for too long can cause other problems, such as constipation or nutritional deficiencies. It’s best to consult with your doctor before starting a low residue diet. They can advise if it’s right for you, how long to stay on it, and how to transition back to your regular diet.

A low residue diet restricts indigestible foods, which minimizes residue. Residue is what’s left behind in the large intestine after digestion. While some people might interchange the terms “low fiber” and “low residue” diet, they’re not the same. A low fiber diet generally means you only avoid high fiber foods.

A low residue diet is more restrictive. You still avoid whole grains and other high fiber foods. But you also avoid tough cuts of meat and limit your intake of dairy products and fats, which can also contribute to gut residue.

A low residue diet focuses on foods that are easy to digest.

Grains

The Food and Drug Administration (FDA) reports that most adults should consume about 28 grams of fiber a day. In contrast, a 2015 literature review suggests a low residue diet should limit dietary fiber to about 10 grams per day. Look for refined or enriched grain products with less than 2 grams of fiber per serving, such as:

  • white rice
  • soft white bread and pasta
  • plain crackers
  • cooked or dry cereals, such as grits

Fruits and vegetables

Choose fruits without seeds or peels, such as:

  • ripe banana
  • soft cantaloupe
  • canned fruits without skin or seeds
  • applesauce
  • juice without seeds or pulp

Choose skinless, seedless cooked vegetables such as:

  • eggplant
  • green or wax beans
  • beets
  • carrots
  • yellow squash
  • pumpkin
  • mushrooms
  • white potatoes
  • canned soft veggies without seeds or peels

Meats and protein

Red meats should be tender and well cooked. You can also have:

  • poultry, fish
  • eggs
  • tofu
  • smooth peanut butter

Dairy

Limit dairy to 2 cups per day. This can include:

  • low fat milk
  • sour cream
  • yogurt
  • cream-based soups
  • puddings or custard
  • ice cream
  • low fat cheeses

Oils and toppings

Among the oils and toppings you can choose are:

  • oil, butter, or margarine
  • mayonnaise and salad dressings
  • whipped cream and sour cream
  • plain gravy
  • smooth condiments
  • honey, syrups, or molasses

Snacks and drinks

Some ideas for snacks and drinks are:

  • plain gelatin
  • plain cookies and cakes
  • pretzels
  • tea or coffee
  • clear broths and soups
  • seedless jams and jellies
  • popsicles
  • hard candies

You’ll want to avoid whole grains and other indigestible foods. Some examples are:

  • products containing whole grains, such as breads, pasta, and cereals
  • wild rice and brown rice
  • popcorn
  • granola
  • dried fruit, raisins
  • pineapple, prunes, berries, and all fruit with seeds or skin
  • potatoes with skin on
  • all raw vegetables and all vegetables with seeds
  • cooked broccoli, Brussels sprouts, cabbage, cauliflower, kale, Swiss chard
  • tough meats with gristle
  • seeds, nuts, coconut
  • baked beans, dried beans, peas, lentils
  • crunchy peanut butter
  • pickles and relishes
  • foods made with cocoa powder
  • marmalades, jams, preserves
  • sauerkraut, horseradish
  • high fat dairy

Minimizing residue should result in smaller and less frequent bowel movements, which can ease symptoms, particularly if you have intestinal strictures or narrowing. It can also lower the risk of developing intestinal obstruction.

However, it’s important to remember that there’s no special diet for people with UC. A low residue diet is meant to relieve symptoms temporarily. It’s not intended for long-term use. That’s because fiber adds bulk to stool, which can keep you regular and promote overall gut health.

Research shows that not getting enough fiber is linked to a higher risk of other diseases such as heart disease and some types of cancer.

A successful colonoscopy depends on how well the colon is cleaned out before the procedure. The prep involves taking specific laxatives at designated times and a clear liquid or low residue diet.

Numerous studies, including randomized controlled trials, suggest that maintaining a low residue diet several days before the procedure is as effective as a clear liquid diet. It’s also associated with higher patient satisfaction because it’s easier to follow.

A 2021 review of research indicates that more people who follow the clear liquid diet report hunger, nausea, and vomiting.

Your healthcare team will provide detailed instructions for colonoscopy prep. This may involve a low residue diet for a few days before transitioning to a clear liquid diet on the last day. You can discuss options with your doctor, but it’s important to follow these instructions and report any deviations prior to the procedure.

A low residue diet restricts or limits indigestible foods. Residue is what remains in the digestive tract after digestion. Less residue creates smaller and fewer bowel movements, which can give the colon time to rest.

A low residue diet means avoiding whole grains, seeds and nuts, and vegetables and fruits with seeds or peels. You’ll also limit dairy products and gristly meats.

Your doctor may recommend a temporary low residue diet. Although the diet can help relieve abdominal pain and other symptoms of a flare-up, it does not treat the underlying disease.

It’s not a good fit for everyone with UC and can lead to nutritional deficiencies over the long term. It’s best to consult with your doctor before starting a low residue diet.