The recommendation to offer directed dietary advice based on metabolic testing and diet assessment for adult patients with calcium-based stones is supported by evidence demonstrating improved outcomes when dietary interventions are tailored to specific metabolic abnormalities. Kočvara et al. conducted an RCT evaluating nonmedical prophylaxis in patients after a first stone event.26 The study showed that a strategy of dietary modification based on individual metabolic abnormalities identified through 24-hour urine testing, along with close metabolic follow-up, resulted in fewer stone recurrence events over a 3-year period compared to a strategy of general dietary advice and limited follow-up.26  Dietary assessment can ascertain if diet is a possible contributor to stone risk in an individual patient (see Table 5 on dietary risk factors to address for prevention of kidney stone recurrence). If urinary volume is low, quantifying habitual daily consumption of beverages should be undertaken to increase fluid intake. If urinary calcium is high, potential dietary contributors to hypercalciuria should be sought, including calcium and vitamin D supplementation (dosage, duration), food sources of salt (as sodium chloride), and the relative proportion of acidogenic foods (e.g., meats, grains) to those with alkaline potential (e.g., fruits, vegetables). Urinary citrate, pH, uric acid, potassium, ammonium, sulfate, and urine urea nitrogen reflect intake of fruits, vegetables, and animal protein. Since urinary sodium reflects salt intake and sodium intake increases urinary calcium excretion, dietary assessment aimed at identifying sources of high salt intake is essential. If urinary citrate is low, average daily fruit/vegetable consumption should be assessed and recommendations made to increase intake. Finally, if urinary oxalate is high, potential dietary contributors should be elicited, including vitamin C supplementation (dosage), use of herbal supplements and other plant extracts, and the relative proportion of oxalate-rich foods (e.g., whole grains, nuts, seeds, certain vegetables) to calcium-rich foods and beverages. Consumption and quantification of dietary fat should also be assessed, particularly in patients with intestinal malabsorption in whom poorly absorbed fatty acids can lead to oxalate hyperabsorption. Engaging and partnering with a registered dietitian and/or gastroenterologist may be helpful as part of a multidisciplinary approach. Although empiric dietary therapy without metabolic testing is common (e.g., discussing fluid intake without knowledge of 24-hour urinary volume), the ability to provide targeted dietary counseling based on identified metabolic abnormalities may improve patient adherence and treatment efficacy. One study showed that limiting dietary counseling to three or fewer targeted recommendations was more effective than a long list of general advice.131