In earlier studies, we demonstrated that increased lipid availability promotes tumor progression through upregulation of HIF‐1α.[15, 16] Our current findings confirm that obesity induced by a HFD leads to an increase in HIF‐1α expression level in tumors, further accelerating tumor progression as we have shown in previous research. The gene discussed is HIF1A; the disease is obesity due to melanocortin 4 receptor deficiency.