The goal of this trial is to assess the effect on the quality of life (QoL) of recommending a fat-free diet versus a balanced WHO diet in symptomatic patients with gallstones and in patients undergoing cholecystectomy for gallstone disease. The main question it aims to answer is: • Is balanced WHO diet as good as low-fat diet in terms of patient reported outcomes when gallstone disease is managed non-operatively (RADIGAL-1) or cholecystectomy is performed (RADIGAL-2)? A validated QoL questionnaire (Gastrointestinal Quality of Life Index - GIQLI) will be administered both at baseline and during follow-up. Analysis of covariance with ordinary least squares estimation will be applied to estimate between-group differences in GIQLI scores at 3 months (primary endpoint). Patient adherence and the disease-related symptoms occurrence or hospitalizations will also be appraised (secondary endpoint). Participants presenting with biliary colic or acute cholecystitis (RADIGAL-1) or undergoing cholecystectomy for gallstones (RADIGAL-2) will: * be randomly assigned to recommending either a fat-free or a balanced WHO diet . * be contacted via phone call to complete the GIQLI questionnaire and document overall adherence to the diets and secondary outcome events. This trial examines the impact of diet on adverse events in gallstone disease, representing the first randomized study to focus on this aspect.