Background and aims: A low-fat diet has been traditionally recommended after cholecystectomy although evidence is lacking. The main aim of the study is to assess either if digestive symptoms improve following the operation and if the restriction of fat in diet does influence these symptoms.

Methods: Symptoms have to be prospectively assessed by the GIQLI score (Gastrointestinal Quality of Life Index) at baseline, and one month after cholecystectomy. A low fat diet or equilibrated diet is randomly assigned to patientes distributed in two groups (N=80) candidates to gallbladder removal. Patients have to follow the prescribed diet and complet a questionnaire of symptoms (GIQLI Symptomantic score).

Introduction The post-cholecystectomy syndrome includes a heterogeneous group of gastrointestinal symptoms presenting after cholecystectomy. However, the term is inaccurate as it is frequently used both for biliary and non-biliary disorders. Liver function and imaging tests are key to rule out biliary disorders such as choledocolithiasis, bile duct injuries or biliary leaks that may have a specific treatment.

Symptoms of non-biliary disorders may persist or arise the novo after surgery. Patients may refer a large variation of symptoms including upper abdominal pain, dyspepsia, diarrhoea, constipation, bloating, flatulence, heartburn or nausea. However, data on prevalence vary enormously. A recent systematic review underscored the lack of accurate data regarding post-cholecystectomy symptoms and only one of the 38 included studies fulfilled all quality criteria. This review showed a great variation of symptoms among the studies, diarrhoea being the most reported postoperative symptom but also with the largest variation across the studies. Moreover, the review found differences between persistent and de novo symptoms in the studies in which this distinction was made, showing that some symptoms considered to be due to the cholecystectomy may, however, be explained by coexisting pathologies such as irritable bowel syndrome or gastrointestinal disorders.

It has also been reported that most preoperative symptoms decrease after surgery except for diarrhoea, which may be a more persistent problem for a proportion of patients. However, data are controversial. Although some studies have reported a frequency of post-cholecystectomy diarrhoea between 5-12%, others support that new onset of diarrhoea is infrequent. A recent large population-based cohort study showed that cholecystectomy was associated with an increased risk of diarrhoea and stomach pain postoperatively, but a weakness of the study may be that questionnaires on gastrointestinal symptoms had not been validated.

Furthermore, a low-fat diet has been traditionally recommended after cholecystectomy for a variable period of time, but there is not a standard guideline on nutrition after surgery . Supposedly, the rationale for this recommendation is that the digestion of lipids may be hindered without the gallbladder. Other recommendations include a gradually increase of the fibre intake. However, literature addressing this issue is scarce and, to our knowledge, only three studies have assessed the effect of a low-fat diet on postoperative symptoms after cholecystectomy. One study failed to find differences in the postoperative symptoms between patients who followed a low-fat diet compared with a normal diet. On the contrary, two studies reported more postoperative symptoms in patients who did not follow a low-fat diet. The current situation is that there is a great variability in the dietary advice given by surgeons after surgery and, in addition, patients may or may not follow their recommendations making it more difficult to know whether specific dietary advice would be really necessary. A previous descriptive study carried by our group has evidenced the expected postoperative improvement in QoL and symtoms following the operation and has shown no differences in GIQLI scores between patients restricting fat intake and those following a diet without restriction.

Therefore, our aims is to prospectively assess symptoms after cholecystectomy by using a validated questionnaire and to assess the potential effect of the type of diet (fat restriction or banaced) followed after cholecystectomy.

Study design Prospective randomized trial in patients admitted at Consorci Sanitari de Terrassa (Barcelona, Spain) for treatment of symptomatic gallstone disease or its complications, evaluating short term postoperative digestive symptoms and if they are influenced by diet. Randomization according a random number table.

Group A: Low fat diet for hyperlipidemic conditions provided by Dietetics team. Group B: Balanced diet provided by Dietetics team

Participants Inclusion criteria: age > 18 years; symptomatic gallstone disease considering biliary pain or complications of gallstones (pancreatitis, cholangitis, cholecystitis).

Exclusion criteria: not willing to participate in the study, inability to understand the information due to mental disorders or language barrier; and severe postoperative complications which could affect the assessment of quality of life after cholecystectomy.

Assessments Prospective collection of patiens demographics, comorbidities and type of surgery. Score of digestive symptoms at baseline, and one month after the surgical procedure. Evaluations carried out during the visit at clinics at baseline and one month after surgery.

Completion the validated version of GIQLI score in Spanish, which has been widely used to assess the quality of life related to several digestive disorders including gallstone disease. The GIGLI is a 36-item patient reported outcomes instrument designed to assess GI-specific health-related quality of life and score from 0 to 4. Higher scores represent a better quality of life and the maximum score is 144. The GIGLI has five subscales: symptoms, physical function, emotional function, social function, and effects of treatment.

The symptoms subscale is the one considered in this study including:

Pain, Bloating, Epigastric fullness, Flatus, Belching, Abdominal noises, Bowel frequency, Restricted eating, Enjoyed eating, Regurgitation, Dysphagia, Eating speed, Nausea, Diarrhoea, Bowel urgency, Constipation, Blood in stod, Burning, Fecal incontinence.

Statistical analysis Descriptions of data will be presented as means and standard deviation for quantitative measures, and as absolute and relative frequencies for qualitative measures. Student's paired t test will be applied to assess differences in the GIGLI score between baseline and one month after treatment. Independent t-test will be applied to assess differences in the GIQLI overtime depending on the type of diet. A p-value <0.05 will be considered statistically significant. Sample size has been evaluated on the basis of standard deviation of the GIQLI score in our precedent descriptive study. Eighty patients per group for a beta error of 20% have to be included. Data analysis will be performed using the statistical Package SPSS version 20.

Ethical approval The study was approved by the Ethics Committees of the Consorci Sanitari de Terrassa. All patients provided written informed consent.

Inclusion Criteria:

- Gallbladder removal because biliary pain or gallstones complications

Exclusion Criteria:

- Major postoperative complications, refusal to participate or not completion of questionnary.