In studies comparing obese and normal weight children from Oaxaca, Querétaro and Mexico City, gut microbiota composition was associated not only with obesity status, but also with metabolic parameters such as TG levels, fasting plasma insulin [42] and HDL cholesterol [25], as well as pro-inflammatory (TNFa) and anti-inflammatory interleukins (IL-10) [86]. Here, TNF is linked to obesity due to melanocortin 4 receptor deficiency.