In children with simple obesity, very low grade inflammatory reactions prevail, reflected here by increase in the leukocyte MMPs inhibitor TIMP-1, decrease in the expression level of MMP-2 and plasma MMP-2 as well as decline in MMP2/TIMP-2, low TNF-alpha levels and negative correlations between the expression of TIMP-2 in leukocyte and liver (AST, ALT) or fat (TTG) inflammatory markers. This evidence concerns the gene TNF and Obesity.