Experimental data suggests, that a pre-interventional caloric restriction might provide kidney protection in this context. This clinical trial investigates if this phenomenon is also applicable in humans. Patients with increased risk for a post-interventional renal failure due to known chronic kidney disease are randomized in 2 groups. Patients of the diet group receive a calorie restriction to 60% of the calculated daily energy rate from day -4 until day -1 (included) pre-intervention (day 0 corresponds to day of intervention). Patients of the control group receive alimentation ad libitum.