Losing weight is a good idea for any of us. But a new study says that if you have kidney disease, it’s even more important to get rid of excess baggage. An article in the Clinical Journal of the American Society of Nephrology said “dieting and exercising cut down on proteinuria — the increased output of protein in the urine — while also preventing kidney function from worsening.” Surgery that brings about weight loss is also a benefit to kidney patients as...