From the guideline document:
Recommendation 1: ACP recommends management with increased fluid intake spread throughout the day to achieve at least 2 L of urine per day to prevent recurrent nephrolithiasis. (Grade: weak recommendation, low-quality evidence)
Recommendation 2: ACP recommends pharmacologic monotherapy with a thiazide diuretic, citrate, or allopurinol to prevent recurrent nephrolithiasis in patients with active disease in which increased fluid intake fails to reduce the formation of stones. (Grade: weak recommendation, moderate-quality evidence)
The evidence for dietary interventions was mixed and not strong enough for the authors to include a recommendation. Also, the guideline states that the evidence was insufficient to support pre-treatment or on-treatment stone analysis or determination of urine composition.