A Requiem for a Standardized Calculation of Ideal Body Weight in Chronic Kidney Disease?

Defining a patient's body weight in order to calculate their protein and energy prescription is an important step for physicians and dietitians working in the field of kidney diseases. Ideal body weight embraces 2 concepts. It is defined both as "the goal weight at which nutritional requirements are met" and "the body weight associated with the lowest mortality for a given height, age, gender, and frame size". Both definitions are not generalizable to people living with chronic kidney disease (CKD), and there is no agreed method for how to define ideal body weight in CKD. The epidemiology of CKD patients is continuously changing; recent years have seen a sharp increase in patients' average age and the prevalence of obesity. This paper critically examines the different ways to calculate a "reference" body weight that can be used to estimate and prescribe a patient's intake of energy and nutrients (proteins in particular) and offers some practical suggestions on how this should be done, particularly those who are overweight or obese.