Weight loss may flush out kidney stone risk

This study looks at whether losing weight with a special meal replacement program (Optifast) can lower the amount of oxalate in the urine of people who are obese and have had calcium oxalate kidney stones. Oxalate is a substance that can form stones. The researchers will measure urine oxalate before and after the weight loss program while participants eat a low-oxalate diet. The goal is to see if weight loss reduces the body's own oxalate production and helps prevent future stones.