Energy balance in predialysis patients on a low-protein diet.
OBJECTIVE
To determine if energy intake on a low-protein diet (0.6 g protein/kg ideal body weight (ibw)/d) with 70% animal protein (Diet A) or 30% animal protein (Diet B) meets energy expenditure derived from measured resting energy expenditure and activity levels.


METHODS
Patients already on a conventional low-protein diet with 70% animal protein kept a 5-day weighed dietary intake, with a 3-day activity diary, and had their resting metabolic rate (RMR) measured. Patients then switched to a diet with 30% animal protein for a minimum of 2 weeks (range, 2 to 16 weeks) and repeated the weighed intake and RMR measurement.


METHODS
Predialysis hospital outpatients.


METHODS
Seven patients were recruited, 5 male. Mean age, 56 years (range, 43 to 78 years); mean serum creatinine 300 micromol/L (range, 180 to 560 micromol/L).


METHODS
Indirect calorimetry used to measure RMR.


METHODS
RMR compared with standard formulae and total energy expenditure compared with dietary intake.


RESULTS
Mean RMR was 5.76 MJ/d (1,385 kcal/d) or 84.9 kJ/kg ibw/d (20.3 kcal/kg ibw/d); which was 108% to 113% of that predicted by standard formulae. Total energy expenditure (RMR plus activity) was 8.35 MJ/d (1,996 kcal/d) or 123.3 kJ/kg/d (29.5 kcal/kg ibw/d). Mean energy intake was 116.3 (27.8 kcal/kg ibw/d) on Diet A and 131.2 (31.4 kcal/kg ibw/d) on Diet B (P = .096) with 3 of the 7 patients meeting their energy expenditure on Diet A and 4 on Diet B.


CONCLUSIONS
RMR of patients with chronic renal failure is within expected range for healthy individuals, and the activity of these relatively fit patients similar to healthy individuals with light to moderate activity. Energy intake on the low-protein diets failed to meet energy expenditure in 4 patients on Diet A and 3 patients on Diet B. Low energy intake may contribute to the development of malnutrition in some patients.
Passey
Caroline
C
Wessex Renal and Transplant Unit, Queen Alexandra Hospital, Portsmouth, England.
Bunker
Valda
V
Jackson
Alan
A
Lee
Harry
H
D000328:Adult; D000368:Aged; D001481:Basal Metabolism; D003404:Creatinine / Q000097:blood; D004032:Diet; D018753:Diet, Protein-Restricted; D002149:Energy Intake; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis
D003404:Creatinine