Dietary compliance
Energy and macronutrient intake were similar at baseline. Compliance with the protein prescription was monitored by a daily food checklist and a food frequency questionnaire
(at baseline, 4 and 12 months) and was also assessed by 24 h urine urea excretion. At baseline urea excretion did not differ significantly between groups (496 31 and
521 32 mmol/24 h in HPD and SPD respectively; p Z 0.41). At 12 months the UUE was not significantly different compared to baseline (p Z 0.13), however the adjusted urea excretion at 12 months was significantly different between groups (519 39, for the HPD and 456 25 for the SPD group; p Z 0.04) indicating compliance to the protein prescription. This was confirmed by self-reported diet data (supplement Appendix 5).