Patients will be randomized to canagliflozin (300mg once daily) or placebo for 5 days and will be studied as inpatients (NIH Clinical Center metabolic unit). Serial blood and urine testing for 4 hours after daily drug administration and at 12, 16 and 24 hours thereafter will be used to assess changes in the pre-specified endpoints. Each subject will be provided a diet containing fixed contents of phosphate, sodium, and calcium throughout the study, beginning 7 days prior to the administration of drug (or placebo).