Eating behavior of animals is controlled by neuronal circuits in the brain, mainly located within the hypothalamus. Hunger is induced by physiological signals, e.g., leptin, informing the brain about energy storages/ deficits in adipose tissue. Additionally, other non‑physiological factors may influence when and what we eat. Those factors include sensory cues of especially palatable food or are entrained by circadian rhythm. Regulation of activity of neurons involved in the control of feeding and metabolism is achieved on many levels of gene expression. We are especially interested in post-transcriptional level of protein translation regulated by microRNAs. These short RNAs serve as a guides for the translation‑inhibiting complex RISC. We have generated transgenic mice with a mutation of the Dicer gene restricted to forebrain neurons of adult mice. The Dicer nuclease is an essential enzyme in the biogenesis of microRNAs. Mice lacking the Dicer gene in the arcuate nucleus of the hypothalamus developed an obesity phenotype due to increased feeding of regular chow diet. We have also examined how different diets – including the standard, high fat diet, Western diet and the ketogenic diet – influence microRNA levels in the blood and preference of mice towards consumed diet. Moreover, we tested cognitive performance of mice fed different diets.