Evaluation of the safety of very-low-calorie diets in the treatment of severely obese patients in a metabolic ward.
UNLABELLED: Nitrogen balance has been measured in 25 (18 f, 7m) obese non-diabetic patients submitted for four weeks to different versions of very-low-calorie diets (VLCD). Patients were divided into four groups and treated as follows: Gp 1 (6f, 4m) by 80 kcal (0.34 MJ) VLCD (17 g protein [= 2.6 g N], tr CHO and fat); Gp 2 (4f, 1m) by 180 kcal (0.76 MJ) VLCD (40 g protein [= 6.4 g N], 2 fat, tr CHO); Gp 3 (4f, 1m) by 80/180 kcal (0.34/0.76 MJ) VLCD (80 kcal during the 1st and 2nd week and 180 kcal during the 3rd and 4th week with the same nutrients as Gps and 1 and 2, respectively). Gps 1-3 received VLCD which essentially contained only protein. Gp 4 (4f, 1m) was treated by a 'mixed' VLCD containing protein and CHO (80 kcal, as in Gp 1 during the 1st and 2nd week; and 180 kcal, 17 g protein + 25.5 g CHO during the 3rd and 4th week of treatment). Weight loss was similar in Gps 1, 3 and 4 (-11 kg) and lower (-8 kg) in Gp 3. Mean daily nitrogen loss was lower in Gp 2 and 3 (-3.2 and -2.9 g N/day respectively). From the 3rd week of treatment nitrogen loss was reduced in Gps 1 and 2 and virtually absent in Gp 3. In Gp 4 nitrogen loss was persistently high (4.3-5.8 g N/day) during the whole period of observation. IN CONCLUSION: at a very low energy intake of below 200 kcal (0.84 MJ)/day dietary substitution of protein with carbohydrates does not ameliorate the nitrogen balance.