Calorie Restriction and Brain Function in Mild Cognitive Impairment

Problems with blood sugar metabolism (i.e., metabolic dysfunction) progressively develop through old age, which is primarily due to obesity and lack of physical activity. Metabolic dysfunction increases the risk for Alzheimer's disease (AD) and negatively impacts memory and related brain function. There is intense interest in developing interventions, particularly non-drug therapies, to combat AD. Recent clinical trials have found that intranasal insulin, which facilitates glucose metabolism in the brain, is able to maintain memory in participants with Mild Cognitive Impairment (MCI), the precursor to AD. While intranasal insulin is a useful, proof-of-concept intervention, it does not affect visceral fat mass and therefore metabolic dysfunction will persist in a given person. The investigators wish to engage participants with MCI in intermittent calorie restriction (CR), to reduce metabolic dysfunction and improve glucose metabolism. Intermittent calorie restriction in this case refers to eating whatever one wants for 5 days, followed by 2 consecutive days of consuming 530 calories via one protein shake with sufficient nutrients to sustain the person. This results in reliable weight loss, which itself improves glucose metabolism in the body and has a wealth of other benefits. (It should be mentioned here that weight maintenance has been shown in studies when participants restrict to 1 day/week).