Protein catabolism in starvation after diets high and low in protein.

Abstract

SUMMARYTwo subjects ate diets high (HP) and low (LP) in protein for 14 days, then continued them for a further three control days, starved for three days (taking only water, salt and vitamins) and then took 300 grammes of sucrose each day for three days.Urea and creatinine clearance rates were 17% to 38% lower on the LP than on the HP diet.Starvation was easily tolerated after the HP diet but was severely distressing after the LP diet.Starvation caused the daily urinary nitrogen loss to decrease after the HP diet from 14·8 to 11·9 grammes, and to increase after the LP diet from 6·8 to 12·2 grammes. The suggested explanation is that protein catabolism reverted in starvation to the rate which was appropriate for metabolizing the amount of protein habitually eaten before the experiment.The practical issue is that tissue destruction during a foreseeable period of starvation, as after surgery, and which is of particular importance to patients with renal failure, is not substantially reduced by short‐term pre‐conditioning with a low protein diet.