Clinical studies indicate alternate-day, intermittent fasting (IMF) protocols result in meaningful weight loss in obese individuals. To further understand the mechanisms sustaining weight loss by IMF, we investigated the metabolic and neural alterations of IMF in obese mice. Male C57/BL6 mice were fed a high-fat diet (HFD; 45% fat) ad libitum for 8 weeks to promote an obese phenotype. Mice were divided into four groups and either maintained on ad libitum HFD, received alternate-day access to HFD (IMF-HFD), and switched to ad libitum low-fat diet (LFD; 10% fat) or received IMF of LFD (IMF-LFD). After 4 weeks, IMF-HFD (∼13%) and IMF-LFD (∼18%) had significantly lower body weights than the HFD. Body fat was also lower (∼40%-52%) in all diet interventions. Lean mass was increased in the IMF-LFD (∼12%-13%) compared with the HFD and IMF-HFD groups. Oral glucose tolerance area under the curve was lower in the IMF-HFD (∼50%), whereas the insulin tolerance area under the curve was reduced in all diet interventions (∼22%-42%). HPLC measurements of hypothalamic tissue homogenates indicated higher (∼55%-60%) norepinephrine (NE) content in the anterior regions of the medial hypothalamus of IMF compared with the ad libitum-fed groups, whereas NE content was higher (∼19%-32%) in posterior regions in the IMF-LFD group only. Relative gene expression of Npy in the arcuate nucleus was increased (∼65%-75%) in IMF groups. Our novel findings indicate that intermittent fasting produces alterations in hypothalamic NE and neuropeptide Y, suggesting the counterregulatory processes of short-term weight loss are associated with an IMF dietary strategy.

Eating disorders represent a set of psychiatric illnesses with lifelong complications and high relapse rates. Individuals with eating disorders are often stigmatized and clinicians have a limited set of treatments options. Pharmacotherapy has the potential to improve long term compliance and patient commitment to treatment for eating disorders. Areas covered: This review will examine the efficacy and safety profile of the FDA-approved medications for the treatment of bulimia nervosa (BN) and binge eating disorder (BED). This will include the evaluation of fluoxetine for BN, and lisdexamfetamine for BED. Safety information will be review from randomized control trials (RCT), open label trials, and case reports. Expert opinion: Fluoxetine for BN and lisdexamfetamine for BED are relatively safe and well-tolerated. Despite these properties, these two medications represent a limited arsenal for the pharmacological treatment of eating disorders. Thus, more research-based strategies are needed to develop safe, effective, and more targeted therapies for eating disorders.