CAT and Obesity: For example, L. sakei, one of the Lactobacillus strains correlated with obesity, is highly resistant to oxidative stress via catalase activity (19, 20) and has a high degree of intraspecies diversity regarding the response to oxidative stress (18) Therefore, we hypothesized that colonization by different Lactobacillus strains could be determined by the oxidative stress levels in the colon, such as those that can be induced in obesity by a high-fat diet.