News Release

Colonoscopy prep may improve with some solid foods

'Low-residue' diet yields better bowel preparation, higher patient satisfaction

Peer-Reviewed Publication

Digestive Disease Week

San Diego, CA (May 23, 2016) -- There's good news for patients who dread the clear-liquid diet before a colonoscopy. A new study finds that patients who ate certain solid foods, considered "low residue," were better prepared for their colonoscopies than individuals who followed the conventional liquid diet. Additionally, researchers saw that these patients who ate foods such as eggs, white bread, cheese, white rice and chicken breast the day before their screening were more comfortable during the 24 hours leading up to the test than individuals who could only have apple juice, chicken broth, coffee and similar clear liquids.

The findings were presented at Digestive Disease Week® (DDW) 2016, the largest international gathering of physicians, researchers and academics in the fields of gastroenterology, hepatology, endoscopy and gastrointestinal surgery.

"Colon cancer deaths can be prevented by colonoscopy, yet tens of millions of patients avoid this life-saving screening," said Jason Samarasena, MD, lead study author and associate clinical professor of medicine in the division of gastroenterology and hepatology at the University of California, Irvine. "Many people often cite the dietary restrictions the day before the colonoscopy as a deterrent for having this screening done."

In this study, the clear-liquid diet group could drink only broth, black coffee, tea and other clear liquids. The low-residue diet group was allowed small portions of protein, carbohydrate and fat at three meals. For their day-before diet, LRD patients could choose from foods such as eggs, yogurt, certain cheeses, breads, butter, rice, lunch meat, chicken breast and ice cream. Both groups then drank standard bowel-cleansing liquid on the night before and the morning of the procedure.

The study tracked 83 patients who underwent colonoscopies at a Veteran's Administration Hospital and a tertiary care facility over a one-year period, comparing results of those who consumed only a CLD on the day prior to the colonoscopy with those patients who ate a planned LRD that included limited portions of select solid foods.

With the low-residue diet group, researchers found a "significantly higher" number of adequate bowel preparations, the cleansing process that is critical to the timely, successful completion of the procedure. This group also expressed a considerably higher satisfaction level for the diet -- 97 percent -- compared to the clear-liquid diet group's 46 percent. In addition, the individuals on the low-residue diet reported "significantly lower" hunger scores on the evening of the prep process, as well as lower fatigue scores on the morning after.

Dr. Samarasena said the low-residue diet contains foods that easily liquefy and do not interfere with the colonoscopy procedure. Researchers also hypothesize that solid foods stimulate bowel movements before the purgative, making the final cleansing process easier. Dr. Samarasena said researchers think the solid foods in the low-residue diet gave patients a higher energy level, possibly making them more tolerant of the entire process. Patients on clear-liquid diet often miss a day of work because of the "fasting" requirement, while the low-residue diet may enable patients to carry on more normal activities since their diets the day before the colonoscopy are less drastic, he added.

Dr. Samarasena indicated that some gastroenterologists are reluctant to try low-residue diet on "challenging" patients who may have multiple illnesses or complications. He said that this study included such patients from the VA hospital, and they benefited from the low-residue diet approach.

"We hope this will change the way practitioners actually operate, and, in turn, help increase patients' willingness to participate in this vital screening process," he said.

Dr. Jason Samarasena will present data from the study "Single day Low Residue Diet prior to Colonoscopy shows improved tolerance and bowel preparation quality over Clear Liquid Diet: Interim results from a U.S. multicenter randomized controlled trial," abstract 723, on Monday, May 23, at 4:58 p.m. PT, in room 6AB of the San Diego Convention Center. For more information about featured studies, as well as a schedule of availability for featured researchers, please visit Dr. Samarasena received funding from Medtronic, Medivators, Olympus and Pentax for DDW research. Faculty disclosures can be found online at


Digestive Disease Week® (DDW) is the largest international gathering of physicians, researchers and academics in the fields of gastroenterology, hepatology, endoscopy and gastrointestinal surgery. Jointly sponsored by the American Association for the Study of Liver Diseases (AASLD), the American Gastroenterological Association (AGA) Institute, the American Society for Gastrointestinal Endoscopy (ASGE) and the Society for Surgery of the Alimentary Tract (SSAT), DDW takes place May 21-24, 2016, at the San Diego Convention Center, San Diego, CA. The meeting showcases more than 5,000 abstracts and hundreds of lectures on the latest advances in GI research, medicine and technology. More information can be found at

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