An area of the brain located close to the hippocampus, in the frontal portion of the temporal lobe. The amygdala governs our responses to fear, arousal, and emotional stimulation. Poor sleep increases activity within the amygdala.

A wavelength of light emitted from natural and electronic sources. Blue light exposure is associated with improved attention span, reaction time, and mood. However, exposure to blue light outside the normal daytime hours may suppress melatonin secretion, impairing sleep patterns. In addition, blue light contributes to digital eye strain and may increase risk of developing macular degeneration.

The body’s 24-hour cycles of biological, hormonal, and behavioral patterns. Circadian rhythms modulate a wide array of physiological processes, including the body’s production of hormones that regulate sleep, hunger, metabolism, and others, ultimately influencing body weight, performance, and susceptibility to disease. As much as 80 percent of gene expression in mammals is under circadian control, including genes in the brain, liver, and muscle.^[1] Consequently, circadian rhythmicity may have profound implications for human healthspan.

The totality of a food’s structure and composition as it is found in its natural state. A food's matrix may contain vitamins, minerals, fiber, carbohydrates, fats, proteins, secondary metabolites (such as polyphenols), and water. Processing or refining of foods often alters the matrix and may modify a food’s glycemic index. Foods that have a high glycemic index can rapidly produce an elevated glucose response.

A type of observational study that searches the genome for small variations, called single nucleotide polymorphisms, or SNPs, that occur more frequently in the DNA of people with a particular disease than in people without the disease. GWAS studies help researchers identify genes that may contribute to a person’s risk of developing a certain disease.

A small organ located within the brain's medial temporal lobe. The hippocampus is associated primarily with memory (in particular, the consolidation of short-term memories to long-term memories), learning, and spatial navigation. Amyloid-beta plaque accumulation, tau tangle formation, and subsequent atrophy in the hippocampus are early indicators of Alzheimer’s disease.

A peptide hormone secreted by the beta cells of the pancreatic islets cells. Insulin maintains normal blood glucose levels by facilitating the uptake of glucose into cells; regulating carbohydrate, lipid, and protein metabolism; and promoting cell division and growth. Insulin resistance, a characteristic of type 2 diabetes, is a condition in which normal insulin levels do not produce a biological response, which can lead to high blood glucose levels.

A broad term that describes periods of voluntary abstention from food and (non-water) drinks, lasting several hours to days. Depending on the length of the fasting period and a variety of other factors, intermittent fasting may promote certain beneficial metabolic processes, such as the increased production of ketones due to the use of stored fat as an energy source. The phrase “intermittent fasting” may refer to any of the following:

• Time-restricted eating
• Alternate-day fasting
• Periodic fasting (multi-day)

The three basic components of the human diet. Macronutrients are consumed in large quantities and provide necessary energy for the body. They include carbohydrates, fats, and proteins.

A hormone that regulates the sleep-wake cycle in mammals. Melatonin is produced in the pineal gland of the brain and is involved in the expression of more than 500 genes. The greatest influence on melatonin secretion is light: Generally, melatonin levels are low during the day and high during the night. Interestingly, melatonin levels are elevated in blind people, potentially contributing to their decreased cancer risk.^[1]

Relating to the period after eating. Postprandial biomarkers are indicators of metabolic function. For example, postprandial hyperglycemia is an early sign of abnormal glucose homeostasis associated with type 2 diabetes and is markedly high in people with poorly controlled diabetes.

A health condition in which blood glucose levels are higher than normal, but not high enough to indicate a diagnosis of type 2 diabetes. Prediabetes can be halted or reversed with dietary and lifestyle modifications, including weight loss, exercise, and stress reduction.

Highly processed grains, starches, or sugars. Refined foods are typically processed via industrial extraction, concentration/purification, or enzymatic transformation and often lack the vitamins, minerals, and dietary fiber of whole foods. Many refined foods have a high glycemic index, which can rapidly produce an elevated glucose response.

Restricting the timing of food intake to certain hours of the day (typically within an 8- to 12-hour time window that begins with the first food or non-water drink) without an overt attempt to reduce caloric intake. TRE is a type of intermittent fasting. It may trigger some beneficial health effects, such as reduced fat mass, increased lean muscle mass, reduced inflammation, improved heart function with age, increased mitochondrial volume, ketone body production, improved repair processes, and aerobic endurance improvements. Some of these effects still need to be replicated in human trials.