When to Follow a Low-Residue Diet

A low-residue diet reduces foods that leave undigested parts (residue) in the colon, such as raw fruits and vegetables, nuts and seeds, beans, whole grains, and more. A low-residue diet limits these and other foods that are especially high in fiber, to reduce stool output. This allows the digestive system (the large intestine, in particular) to rest, as bowel movements will become smaller and less frequent.

Your healthcare provider may recommend a low-residue diet for several reasons, such as healing a gastrointestinal condition or as part of the preparation for a colonoscopy.

This article discusses the benefits of a low-residue diet, how the diet works, factors to consider, as well as other similar diets to know about.

Benefits of a Low-Residue Diet

Your health care provider might recommend following a low-residue diet if you are:

• Recovering from recent bowel surgery (such as ileostomy, colostomy, or resection)
• Preparing for a colonoscopy
• Experiencing worsened symptoms of abdominal pain, cramping, or diarrhea
• Having an active flare-up associated with a gastrointestinal condition, such as Crohn’s or diverticular disease
• Experience bowel-related complications from radiation treatment

Foods that are high in fiber, especially “roughage,” tend to leave behind some plant particles in your colon that can’t be digested. This undigested matter mostly comes from fruits, vegetables, nuts, seeds, beans, and whole grains, though dairy products can also leave residue behind.

This residue helps keep stools bulky and moving through the intestines and usually doesn’t present a problem. However, in situations when your bowel needs to be slowed down to allow for healing, adjusting your diet is the primary solution.

A 2017 review highlights that limiting foods with fiber and those that leave a residue may not only play an important role in reducing inflammatory bowel disease (IBD) symptoms but also in remission.

However, the authors also state there is an overall lack of uniformity or clarity amongst research studies so more well-designed studies are needed to better understand how diet and IBD are connected.

Similarly, while there is only limited evidence concerning low-residue diets that include solid food, research has demonstrated a primarily liquid low-residue diet may be beneficial for people who have Crohn’s disease.

Bowel prep—removing waste from the colon—is required before bowel surgery, and a low-residue diet plays a role in this process. It can also help during surgery recovery.

The diet can also be used to transition from a clear liquid back to a regular diet after surgery or if you develop a bowel obstruction.

For people who don't have bowel disorders, research has shown that low-residue diets may be a beneficial part of colonoscopy prep as well.

How a Low-Residue Diet Works

Creating a meal plan that puts as little demand on the digestive tract as possible is the rationale behind a low-residue diet. You'll be able to adapt the diet to your preferred eating schedule, but the content and size of your meals will be different from what you're used to.

Your fiber intake is the biggest change you'll make on a low-residue diet. For an adult eating a regular 2,000-calorie-per-day diet, the recommended daily fiber intake is at least 25 grams (g) per day. On a low-residue diet, you’ll consume just 10 to 15 g of fiber daily.

Your healthcare provider and a registered dietitian or nutritionist can help you put together meals that work with these dietary restrictions and provide adequate nutrition. 

Duration

The amount of time you need to follow a low-residue diet depends on the reason your healthcare provider recommended it.

Adhering to a low-fiber or low-residue diet for up to a week before a colonoscopy can make prep easier. 

The same can be said for surgery preparation (e.g., for a colectomy), but you may need to continue on your low-residue diet after your procedure until your intestines finish healing.

If you have a digestive disorder, following a low-residue diet (or a modified version) may be recommended for a longer period or on an ongoing basis.

What to Eat

While your choices will be limited on a low-residue diet, it is possible to meet your daily nutritional requirements if you include a lot of variety.

Use the low-residue diet recommendations as a guide, but know that research indicates people with gastrointestinal disorders use trial and error to determine which foods contribute to their symptoms.

Even if two people have the same symptoms, they won't necessarily feel better eating the same foods. Some people with diverticular disease, for example, actually report fewer symptoms when eating a high-fiber, rather than restricted fiber, diet.

These are sample of foods to choose and foods to avoid:

Fruit: Fruits like peaches, pumpkin, apricots, and bananas are fine as long as you remove pits, seeds, peels, and skins. Fruits with seeds not easily removed, like berries, are not recommended. Canned fruit and fruit cocktail cups may be OK, as long as they don't contain fruits on the avoid list (berries, for example). Avoid dried fruit, especially raisins, figs, dates, and prunes.

Most fruit juice is acceptable as long as you choose varieties without pulp. You will want to avoid high-fiber prune juice, however. 

Vegetables: Peeled vegetables that are well-cooked (or canned) are approved, including carrots, beets, and green beans. Raw vegetables are typically too difficult to digest—particularly chewy and tough varieties like celery. You may choose to completely avoid leafy greens like lettuce, though they may be tolerable when cooked.

White potato can be eaten mashed or boiled without the skin. Avoid any pickled vegetables or sauerkraut.

Grains: Stick to bread and pasta made with refined carbohydrates. Choose white rice instead of brown rice, wild rice, or rice pilaf. Soda crackers and melba toast are approved.

Use white bread or sourdough bread for making toast and sandwiches instead of whole grain bread like whole wheat, pumpernickel, and rye. Avoid high-fiber snacks such as popcorn.

Try hot breakfast cereals like Farina instead of oatmeal. Grits and cream of wheat are other options. Cold cereal choices include puffed rice or cornflakes. Avoid bran and any cereals with nuts, seeds, berries, and/or chocolate.

Dairy: Limit milk products to no more than 2 cups per day. Low-lactose dairy options like cottage cheese may be tolerable. Yogurt can be part of your daily servings of dairy but choose plain flavors. Fats like butter and margarine are approved as tolerated.

Protein: Eggs can be soft-boiled or poached. Avoid nuts and seeds; nut butter is OK as long as you stick to creamy varieties.

Choose lean meat without gristle and cook until tender. Avoid frying meat or adding heavy spices or seasonings. Tofu is an approved protein source for meals and can also be used as a base for shakes and smoothies. Avoid beans and legumes including peas and lentils. 

Beverages: Drink plenty of water. Carbonated beverages like seltzer are allowed, though they may increase symptoms of gas. Caffeine from coffee, tea, and soda are aggravating for some people with digestive disorders, though they are permitted on a low-residue diet.

Avoid all alcoholic beverages including wine, beer, and cocktails. If your healthcare provider suggests caloric or nutritional supplements (such as Boost or Ensure), you may want to look for options that do not contain dairy (or limit intake to no more than 2 cups if it's dairy-based).

Desserts: Plain cakes and cookies made with refined white flour and sugar are typically easy to digest. Sweets that contain chocolate, coconut, nuts, seeds, or dried fruit should be avoided. Gelatin and ice pops are especially helpful if you are on a clear liquid diet. Jelly, jam, and honey are approved as tolerated, given they don’t contain seeds or pits. 

Recommended Timing

If you have digestive symptoms you’re hoping to manage through diet, meal timing is important. 

For example, you might find you feel best when you can sit down to three regular, balanced meals each day. Or, you might find having smaller meals more frequently, along with nutritious snacks, is better for your digestion.

Listen to your body; if you have a digestive disorder, what works best for you may depend on whether or not you’re having symptoms.

Remember, too, that eating less fiber means you're likely to be hungry sooner because food is digested in the stomach faster. You might need to snack more frequently throughout the day. Increasing your fluid intake can also help. 

Cooking Tips

When you’re preparing food, think about how you can make it softer or less dense. Generally speaking, frying or grilling food can make it “heavier” in terms of digestion, while methods like poaching or steaming tend to lighten it. Many foods can also be easily microwaved.

Also, think about the ingredients a food has been cooked in or with. Dense fats like butter or foods topped with cheese can make a relatively low-fiber meal harder to digest. Cooking oils can be used as tolerated. 

If spices or seasonings are irritating to your intestines, leave them out of recipes or avoid dishes that include them.

As mentioned, remember to remove peels, skins, and seeds from fruits and vegetables as you prepare meals.

Modifications 

A low-fiber or low-residue diet can be difficult to navigate if you have diabetes. Many of the recommended foods (such as white bread) are simple carbohydrates, which will increase your blood sugar. 

If you have diabetes and need to be on a low-residue diet, continue to pay attention to portion sizes and count carbohydrates for each meal and snack. When choosing low-residue foods, focus on approved veggies and lean protein. 

Eating a well-balanced diet is especially important if you are pregnant or nursing. If you have a digestive disorder, pregnancy may exacerbate symptoms. Your healthcare provider might suggest you make some temporary changes to your low-residue diet or take supplements.

If you are on a low-residue diet while preparing for a colonoscopy, you will need to avoid red or purple foods and drinks (such as beets, purple sports drinks, or red gelatin). These foods can temporarily discolor the tissue of your colon, making it look like blood during the test. 

Low-Residue Diet Considerations

In addition to thinking about what you can and can't eat, there are a few other considerations to keep in mind.

General Nutrition

Following a restricted diet can make it difficult to consistently eat enough calories and get adequate nutrition. Your healthcare provider may suggest you take nutritional supplements to help prevent deficiencies in key vitamins and minerals. 

Your healthcare provider may order blood tests to check your vitamin and electrolyte levels. If you have a deficiency, slight adjustments to your diet or taking supplements may be all that's needed to correct it.

If you need to be on a low-residue diet for a lengthy period, consider working with a registered dietitian to ensure you’re eating as well-balanced a diet as possible. 

Sustainability and Practicality

Many foods approved on a low-residue diet are plentiful at markets and grocery stores. Stock up on non-perishable items like boxed pasta and canned goods to have on hand if symptoms pop up suddenly. 

If you are unable to prepare fruits and vegetables according to the diet (peeling and cooking, for instance) many varieties can be bought pre-cut, pre-cooked, or already peeled. You can also get pureed versions of many fruits and vegetables, which can be eaten as-is or added to smoothies, sauces, etc.

Flexibility

Whenever you're planning to change how you eat, you'll need to take the reality of your day-to-day schedule into account. Some diets can be challenging if you can't plan ahead, but many approved foods on a low-residue diet are readily available at the grocery store or can be easily packed as a snack. 

Even dining out on a low-residue diet is possible as long as you ask about how food is prepared, what ingredients are included in the dish, and know when to ask for modifications (such as swapping white bread for wheat). 

Dietary Restrictions

If you follow a special diet for another reason, such as a food allergy, carefully consider any diet that further restricts what you’re allowed to eat. 

For example, if you're on a gluten-free diet, you probably already avoid many of the whole grains and carbohydrates that are on the "avoid" food list.

However, you'll need to pay careful attention to the ingredients commonly used to make gluten-free bread, pasta, and cereals, including nuts, seeds, and brown rice. 

If you follow a vegan or vegetarian diet, low-residue animal products, such as meat, eggs, and dairy, would be excluded. The typical alternative sources of protein for plant-based diets, like beans and legumes, are not recommended on a low-residue diet. 

Support and Community

If you are struggling or have questions, your healthcare provider and other members of your healthcare team can offer practical answers and reassurance.

While they can be helpful, if you have a chronic disorder, there may be times when you'd like to talk to other people who are experiencing similar issues. Those with experience can give you a different perspective and share what has worked for them, as well as provide an ear when you need to share your frustrations.

Ask your healthcare provider if your local community offers in-person support groups. You can also research online groups or message boards to join. If you have a specific condition, such as ulcerative colitis, look for hashtags on social media to find patient-run support networks as well.

Cost

If you need to take nutritional supplements or probiotics, you may find them to be a high-cost part of your diet. Ask your healthcare provider and health insurance provider if these items can be prescribed for you. If your health insurance won’t cover the cost, ask about promotions, coupons, or patient assistance programs for prescriptions. 

Side Effects

If you are following a low-residue diet for a longer period, be aware of the possible signs of a nutritional deficiency: 

• Fatigue, shortness of breath, and chest pain may indicate iron deficiency anemia.
• Inadequate vitamin C can lead to symptoms of scurvy, such as bleeding gums; fatigue; irritability; joint, muscle, or leg pain; and skin changes.
• Vitamin B12 deficiency can cause neurological symptoms, such as memory problems, numbness and tingling in your limbs, balance problems, weakness, and fatigue. 

You may also experience constipation while on a low-fiber diet. Staying hydrated will help you avoid this. Following a low-residue diet doesn't mean you can't have any fiber at all. So if constipation is an issue, a fiber supplement may be recommended.

General Health

If a low-residue diet isn't enough to treat your symptoms, your healthcare provider might suggest you try a probiotic and/or you may be prescribed a course of antibiotics.

Probiotic supplements don't treat digestive disorders, but an imbalance of gut bacteria may cause or worsen symptoms.

Antibiotics may be necessary if you have small intestinal bacterial overgrowth (SIBO) or another type of bacterial infection, or if you are undergoing surgery.

Low-Residue vs. Other Diets

A low-residue diet has very specific requirements, but it is similar to other types of diets commonly used to treat bowel disorders. 

Low-Fiber Diet

A low-fiber diet is part of a low-residue diet. The main difference between the two diets is that if you’re following a low-residue diet, you’ll have added restrictions. 

One of the biggest differences between a low-fiber diet and low-residue diet is how much dairy is allowed.

Dairy is allowed on a low-fiber diet to the degree you can tolerate it. But if you're on a low-residue diet, you can only have 2 cups of dairy products a day.

Your daily fiber allowance on both a low-fiber and low-residue diet will be about 10 to 15 g per day.

Low-FODMAP Diet

Fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) are found in many of the foods we eat. Some people find FODMAP-containing foods cause or worsen symptoms of digestive disorders like irritable bowel syndrome (IBS), such as bloating, abdominal pain, and diarrhea. 

A low-FODMAP diet is similar to a low-residue diet, but not entirely. Many of the foods you can eat on a low-FODMAP diet are not permitted on a low-residue diet, including nuts and seeds, broccoli, brown rice, and oats. Foods with a lot of fiber such as legumes and beans, apples, and okra are also considered high-FODMAP foods.

Dairy typically isn’t allowed on a low-FODMAP diet, but on a low-residue diet, you can have less than 2 cups of dairy each day if you tolerate it. 

BRAT Diet

The BRAT Diet is commonly used to treat temporary digestive upsets like viral stomach flu or food poisoning. BRAT is an acronym for bananas, plain white rice, applesauce, and toast made with refined white bread—foods that are easy to digest if you are experiencing symptoms like nausea and diarrhea. 

While the BRAT Diet works well in the short term, you shouldn’t stay on the diet for a long time unless your healthcare provider is supervising you. It’s difficult to get all the energy and nutrition your body needs if you’re only eating small amounts of a limited group of foods. 

Summary

A low-residue diet limits foods such as raw fruits and vegetables, seeds and nuts, beans, and whole grains because they leave undigested parts (residue) in the colon. A low-residue diet may be recommended for digestive disorders, colonoscopy prep, or recovery from surgery.

The longer you are on a low-residue diet, the harder it becomes to stay properly nourished. Work with your healthcare provider and a registered dietitian to create a meal plan that addresses your symptoms, preferences, and nutritional needs.