TLR4 and Insulin resistance: While some studies have similarly reported that loss of function of either TLR4 or CD14 protects against body fat gain, insulin resistance, and inflammation in mice fed high-fat diets15–20 other studies have not supported such a role for CD1421,22 or TLR423–26 in the control of body weight, while loss of TLR4 still mitigated some other negative metabolic effects of HFD feeding.