Fasting has numerous biological, physical and mental health advantages or that as some physicians cure their patients by prescribing fasting to them. Fasting protects people from many diseases such as cancer, cardiovascular diseases, and diabetes complications. The main health-promoting effects of fasting are increased production of neurotrophic factors, neuroendocrine activation, hormetic stress response, reduced mitochondrial oxidative stress, general decrease of signals associated with aging, and promotion of autophagy. This article briefly describes the molecular view of the effects of fasting on human health, according to our laboratory results, which are obtained by biophysical and biochemical methods. Based on our results, the presence of 3-β-hydroxybutyrate (BHB) as a liver produced metabolite in the fasting condition protects the body against toxicity of human serum albumin and insulin glycation products. Our results demonstrated that, BHB protects protein against sugar binding, inhibits the alteration of the protein structure and diminishes AGEs formation. By this way, BHB inhibits friend to foe transformation in proteins to protect us against diabetic complications.