Clear Liquid Diet

Article Author:
Julianne Oates
Article Editor:
Sandeep Sharma
3/18/2019 11:36:32 PM
PubMed Link:
Clear Liquid Diet


A clear liquid diet is a special type of diet that may be ordered by a healthcare provider that is made up of only liquids/semi-liquids that are clear and not opaque at room temperature. Some items that may be allowed include water, ice, fruit juices without pulp, sports drinks, carbonated drinks, gelatin, tea, coffee, clear broths, and clear ice pops. Items can have color as long as they are see-through. Items such as milk and orange juice are not considered clear liquids because they are not clear and take more effort for the digestive system to breakdown. Depending on individual patients and their previous dietary restrictions related to sugar intakes, food items may be allowed such as honey, sugar, and clear hard candies. The clear liquid diet assists in maintaining hydration, it provides electrolytes, and offers some level of satiety when a full diet is not appropriate.  


The digestive system begins with the mouth. Saliva is released and facilitates several functions, including swallowing. Swallowing clear liquids occurs by voluntarily moving the liquid to the back of the mouth. Next, reflexively, the soft palate closes the nasal passages to prevent the liquid backflow; the trachea gets blocked by the epiglottis for the same purpose, and the esophagus relaxes to allow the liquid to enter. Peristalsis moves the liquid down in wave-like contractions into the stomach. Peristalsis persists throughout the gastrointestinal tract to propel the contents through. From the stomach, the digestive enzymes breakdown proteins into amino acids; fats into fatty acids and glycerol; and carbohydrates into simple sugars. Clear liquids are the easiest for the body to break down because they have very few proteins and fats and are predominantly made up of carbohydrates which are easily digestible. This digestive mix is called chyme, and it moves into the small intestine where the walls of the small intestine (via lumenal projections called villi) absorb nutrients and water. The large intestine absorbs water and changes the liquid into the stool. Lastly, this stool moves to the rectum and is excreted through the anus.  


Indications for a clear liquid diet include a number of medical conditions or surgical procedures.

Examples include[1]:

  • Prior to procedures
  • Post-operative
  • Diverticulitis
  • Nausea, vomiting, diarrhea


While there are no formal contraindications for a clear liquid diet, there are some significant considerations to think about when utilizing this diet choice.

Several choices available to this diet are high in carbohydrates and simple sugars. People with diabetes should be cautious about their options and are at risk for hyper- and hypoglycemia. They should also check their blood sugars regularly when on this diet.

Several choices of this diet are thin liquids. These options put people who have dysphagia, or difficulty swallowing, at risk for aspiration. Some of the agents utilized to thicken liquids are starches, which may be a consideration for their use. Ensure clear communication between the health care team and patient when ordering the clear liquid diet for a patient with dysphagia.

This diet should not last for a duration of more than a few days when possible. It is challenging to provide the necessary nutrients and calories needed while maintaining a clear liquid diet. Transition to solid foods should take place as rapidly as possible and an interprofessional communication can produce the best patient outcomes.[2]


If a person is in an in-patient facility, the nurse will review the diet order.  It is vital for all healthcare team members to have full understanding regarding what items are acceptable in a clear liquid diet.  Conversations with the an interprofessional team should occur as needed about the patient's readiness to advance the diet. 

If a person is going to be utilizing a clear liquid diet at home, it is vital for the healthcare team that orders the diet to ensure proper patient education when ordering such a diet.  Handouts that patients can take home are a helpful aid. 

Other hospital personnel that comprises the healthcare team include healthcare techs, kitchen staff, dietary staff, and potentially the speech therapist. 


It is recommended to minimize gastric volume at the time of surgery to lower the risk of aspiration with anesthesia or sedation. Different food items are digested and emptied from the stomach at different rates. To mitigate this risk, most providers recommend not to eat solid foods eight hours prior to the procedure and may allow clear liquids up to two hours prior to procedures.[3]

Often, a clear liquid diet is ordered before gastrointestinal procedures, such as endoscopes or colonoscopies, in addition to the bowel preparation medication that is prescribed. It is critical to adhere to this process before the procedure so the provider can fully assess the GI tract. Another consideration when choosing clear liquids for this situation is to avoid red and orange colored items. The color residue may appear blood-like during the procedure and is best to avoid those colored items to alleviate inaccuracy of testing.[4][5]

During a procedure that utilizes sedation and/or general anesthesia, a clear liquid diet may be ordered as part of the recovery process. Using a clear liquid diet provides an opportunity to assess many factors post-operatively. Remember that the patient will likely be sleepy during the postanesthesia phase of care. They may have been intubated and their throat may feel sore or dry. It is essential to wait until they are ready to try their diet. It is okay to wait until they ask for something to drink before offering something. If they are too drowsy to control their swallow then they are at risk of aspiration. When the patient asks for something to drink, sit them up as they can tolerate. Start with a few ice chips and assess their ability to control their swallow reflex. If they do not cough or clear their throat after the ice chips they are likely ready to try a sip of water. Again, assess the patient’s swallowing ability with the first sip. If they do not demonstrate any difficulty they are likely ready to advance to other clear liquids as ordered. If the patient is drowsy, coughs, clears their throat, or is unable to swallow, they may need additional time to recover from the anesthesia to try again, or they may need further follow up with speech therapy for a formal swallow study. If the patient unable to keep their airway clear, do not continue diet without notifying provider. Wait for 1 to 2 hours after the throat has been numbed for any ENT or bronchoscopic procedure.[6]

Sometimes a provider will order a clear liquid diet for a patient who has a GI disturbance, such as diverticulitis, nausea, vomiting, or diarrhea. Utilizing a clear liquid diet for these instances allows for bowel rest and healing. Some foods are aggravating to the GI tract and avoiding them but still allowing clear liquids will maintain hydration, electrolytes, and satiety while limiting the strain of digestion.[7]

Enhancing Healthcare Team Outcomes

Always utilize the facility policy for specific instructions. It is essential to be aware of what constitutes a clear liquid item and what is not. Providing clear communication with the healthcare team is vital especially with special circumstances such as patients with diabetes or dysphagia. Patient education should include not only what is the clear liquid diet but also why they are on this diet. Keep in mind the transition to solid foods and reassess readiness regularly.[8][6][9]


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