Slimming treatment efficiency and changes in serum lipids and lipoproteins in obese adolescents

The efficiency of a slimming treatment, which is the quantity of lean body mass (LBM) lost for each kilogram of body fat reduced, measured by Efficiency Index (EI), was investigated in nineteen obese male adolescents aged 10-14 years who lost weight during four weeks of a treatment combining hypoenergetic diet (0.18 MJ/kg of expected body weight for stature), physical exercise and psychological support. Anthropometric assessment of adiposity including body composition using Parízková and Roth's regression equations was made before onset of treatment and after 7, 14 and 28 days. Simultaneously, blood samples were drawn for serum lipids and lipoproteins. A total of seventy six observations and assessments of treatment efficiency and changes of lipid profile between every two observations were carried out. Significant correlations were found between EI values and changes in Total Cholesterol and Total Cholesterol/HDL Cholesterol ratio at the three evaluations carried out. Though HDL-Cholesterol level increase was not significant, its variations were strongly correlated with EI during the first and second assessments. Differences found in the magnitude of increase in nonesterified fatty acids (delta NEFA), suggest that lipolytic mechanisms were not uniformly impaired. Treatment efficiency and delta NEFA were lower in subjects with lesser adiposity related to muscle mass at the middle third of the upper arm (measured through Energy/Protein Index). Triglycerides and LDL + VLDL Cholesterol levels showed little variations. The achievement of a high treatment efficiency is not only necessary for preserving growth, but also for the significant decrease which occurs in some lipid fractions when EI is below 0.5.