Until recently, primary cilia were considered relics from our skinbrain ancestors with no specific function. In the past decade it became evident that primary cilia are involved in a few fundamental physiological processes such as body energy homeostasis, body weight regulation, reproduction etc. The current understanding is that the primary cilium represents a sensory device of the cell which detects both chemical and mechanical environmental stimuli. These stimuli are then transmitted through the fine cargo intra-flagellar transport system which is linked to a few of the intracellular signalling systems. Mutations in primary cilium components result in a few human conditions, known as ciliopathies, such as Bardet-Biedl and Alström syndrome. Fat aussie is a newly identified mouse variant which inherits a mutation (foz) in the cilium component Alms1 and partially recapitulates human Alström syndrome. The phenotype includes morbid obesity followed by type 2 diabetes, steatotic liver disease and reproductive failure. We discuss specific aspects of the fat aussie phenotype such as obesity pathogenesis, spermatogenesis arrest and high fat diet induced transition of the benign steatosis to steatohepatitis in foz/foz mice. The better understanding of the role of primary cilia in body energy and body weight regulation, glucose and lipid metabolism and reproduction could pinpoint to new therapeutic targets in the treatment of some of the most prominent medical problems of our time.