Reducing the level of insulin can impair cognition. Insulin, a hormone, helps neurons in the hippocampus and frontal globe take up glucose for energy, it regulates neurotransmitters (acetylcholine) which are crucial for memory and learning. Insulin encourages plasticity of our brain, a process through which neurons change shape, make new connections and strengthen existing ones. When a person is obese, insulin is reduced drastically. Obesity, in fact, triggers the release of inflammatory and metabolic stress molecules inside liver and fat cells disrupting insulin action and leading to high blood glucose levels and insulin resistance. Remember that alcohol also reduces the number of insulin receptors in the brain. Therefore, attention to diet and alcohol!