The Czechoslovak low-energy protein diet contains 1559 kj per day, incl. 33.0 g protein, 50 g carbohydrate, 4.0 g fat, 6.0 g fibre and recommended vitamin and mineral allowances. The diet was administered to 75 subjects with a mean age of 39.88 +/- 1.21 years and a body weight of 112.57 +/- 2.89 kg, and a body weight index (BMI) of 39.44 +/- 0.94, for 28 days. During treatment the body weight declined by 9.67 +/- 0.41 kg and the BMI by 3.74 +/- 0.20. At the same time there was a significant decline of the total cholesterol (p less than 0.001), LDL cholesterol (p less than 0.001), HDL cholesterol (p less than 0.01) and triacylglycerols (p less than 0.05). In 20 subjects with hyperlipidaemia similar changes of the total cholesterol and LDL cholesterol were recorded, while the decrease of HDL cholesterol (p less than 0.001) and triacylglycerols (p less than 0.001) was more marked. The nitrogen balance became during the fourth week on the diet positive (+0.64 g), there was a transitory decline of the total protein concentration. The serum amino acid concentration did not change significantly with the exception of isoleucine, the level of which increased. The serum immunoglobulin concentration did not change significantly. It may be concluded that the low-energy protein diet has a favourable impact on the lipid metabolism, without a marked negative effect on the protein metabolism.

Keywords: Adult; Amino Acids /metabolism/; Diet, Reducing; Dietary Proteins /administration & dosage/; Energy Intake; Humans; Immunoglobulins /analysis/; Lipids /blood/; Nitrogen /metabolism/; Proteins /metabolism/