Amino acid composition and protein contents of selected very low energy reducing diets

The contents of total protein, amino acids including 5-hydroxylysine and 4-hydroxyproline, and estimated collagen of five very low energy reducing diets as therapeutic weight reduction treatment for the obese were determined as potentially useful indices for evaluating their protein quality. The amino acid composition and protein content of these diets varied with the amounts of plant or animal protein additives and ingredients used to formulate them. There were significant differences (P 0.001) in their total essential amino acid contents, compared to the FAO/WHO reference pattern value of 33.9%, with the casein- and soybean-based diets ranging from 46.4 to 46.9% and the connective tissue-based diets varying from 12.7% to 18.8%. Calculated protein efficiency ratios ranged from 2.5 to 2.7 in the casein and soybean diets and from 1.0 to 1.4 in the connective tissue-based diets. Total collagen in connective tissue-based diets (51.3-65.5%) was determined from the amounts of 5-hydroxylysine found in their 96-h acid hydrolysates, and total connective tissue proteins (80.3-84.1%) were determined from the amounts of 4-hydroxyproline present. Very low energy diets when used without strict medical supervision can be life threatening