Energy expenditure following oral glucose load in ten uremic patients before and after three months on a ketoacid-supplemented very-low-protein diet

We have previously shown that a ketoacid-supplemented very-low-protein diet (KSVLPD), which has been proposed to slow down the rate of progression of chronic renal failure (CRF), improves tissue insulin sensitivity and decreases hyperinsulinemia in predialytic uremic patients. However, this diet may interfere with nutritional status. The aim of this study was to study basal energy expenditure (EE) and EE after an oral glucose load in patients with CRF before and during a KSVLPD (0.3 cal x kg wt(-1) x d(-1) supplemented with aminoacid and ketoanalogs) using oral glucose loading in combination with indirect calorimetry. We also monitored body weight and analyzed body composition by dual-energy x-ray (DEXA) during KSVLPD. In the third month of KSVLPD, no significant change in total body weight was observed, but DEXA showed a decrease in lean tissue mass (LTM; 46.2 +/- 3.6 kg before v 44 +/- 3.4 kg in the third month; P.01) and an increase in body fat mass (20.1 +/- 2.4 kg before v 21.3 +/- 2.4 kg on KSVLPD; P.05). Postabsorptive plasma glucose level was significantly lower, and glucose oxidation and energy expenditure per LTM were significantly increased (EE, 20 +/- 0.8 cal x kg LTM(-1) x min(-1) before diet v 21.9 +/- 1.1 cal x kg LTM(-1) x min(-1) after 3 months on KSVLPD; P.01). Plasma glucose and serum insulin levels were significantly lower after glucose loading, and glucose oxidation increased. EE values were significantly higher after the oral glucose load, and cumulative EE after oral load increased from 20.7 +/- 0.7 cal x kg LTM(-1) x min(-1) before the diet to 22.9 +/- 1.1 cal x kg LTM(-1) x min(-1) in the third month of KSVLPD; P.001). Glucose oxidation was higher and cumulative glucose storage was decreased after diet (29.6 +/- 4.2 g v 20.9 +/- 3.4 g on KSVLPD; P.01). We conclude that KSVLPD increases EE in the postabsorptive state and after an oral glucose load with an adaptation of lean tissue mass in the third month of the diet. Therefore, during KSVLPD, strict monitoring of dietetic management is necessary to maintain energy requirements at high levels appropriate to the new EE.