Although ABL and periodontal osteoclast numbers were not affected by diet regardless of ligation or sham-ligation, leukocyte and macrophage numbers and protein levels of tumor necrosis factor α (TNF-α) in the periodontium and serum interleukin (IL)-6 levels were downregulated in periodontitis mice fed a high-fat diet. This evidence concerns the gene IL6 and periodontitis.