Reportedly, MCT1 haploinsufficiency in mice reduces MCT1 protein levels to nearly half in major metabolic tissues such as liver, brain, and white adipose tissues, and these mice are resistant to diet-induced obesity and liver steatosis and inflammation (Lengacher et al., 2013; Carneiro et al., 2017; Hadjihambi et al., 2023). Here, SLC16A1 is linked to obesity due to melanocortin 4 receptor deficiency.