An enzyme that plays multiple roles in cellular energy homeostasis. AMP kinase activation stimulates hepatic fatty acid oxidation, ketogenesis, skeletal muscle fatty acid oxidation, and glucose uptake; inhibits cholesterol synthesis, lipogenesis, triglyceride synthesis, adipocyte lipolysis, and lipogenesis; and modulates insulin secretion by pancreatic beta-cells.

The practice of long-term restriction of dietary intake, typically characterized by a 20 to 50 percent reduction in energy intake below habitual levels. Caloric restriction has been shown to extend lifespan and delay the onset of age-related chronic diseases in a variety of species, including rats, mice, fish, flies, worms, and yeast.

The first enzyme in the electron transport chain. Complex I (also known as NADH Coenzyme Q oxidoreductase) is found in the mitochondria of eukaryotes and the plasma membranes of some bacteria. It couples the oxidation of NADH and the reduction of ubiquinone to provide the electrical gradient necessary to produce ATP. Complex I and its partner enzyme, complex III, are the primary sites of reactive oxygen species production in mitochondria. Mutations in complex I are associated with many disease conditions, including Parkinson's disease and Alzheimer's disease.

A metabolic pathway in which the liver produces glucose from non-carbohydrate substrates including glycogenic amino acids (from protein) and glycerol (from lipids).

Biological responses to low-dose exposures to toxins or other stressors such as exercise, heat, cold, fasting, and xenohormetics. Hormetic responses are generally favorable and elicit a wide array of protective mechanisms. Examples of xenohormetic substances include plant polyphenols – molecules that plants produce in response to stress. Some evidence suggests plant polyphenols may have longevity-conferring effects when consumed in the diet.

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 end results of a physiological process in which your body has biochemically, physiologically, and metabolically shifted from using primarily glucose to using glucose and equal, or in some cases more, fatty acids and ketones for fuel. Being adapted represents an increase in production, utilization and metabolism, general oxidative capacity of cells, as well as actual ability to transport ketones.

A diet that causes the body to oxidize fat to produce ketones for energy. A ketogenic diet is low in carbohydrates and high in proteins and fats. For many years, the ketogenic diet has been used in the clinical setting to reduce seizures in children. It is currently being investigated for the treatment of traumatic brain injury, Alzheimer's disease, weight loss, and cancer.

An enzyme that participates in genetic pathways that sense amino acid concentrations and regulate cell growth, cell proliferation, cell motility, cell survival, protein synthesis, autophagy, and transcription. mTOR integrates other pathways including insulin, growth factors (such as IGF-1), and amino acids. It plays key roles in mammalian metabolism and physiology, with important roles in the function of tissues including liver, muscle, white and brown adipose tissue, and the brain. It is dysregulated in many human diseases, such as diabetes, obesity, depression, and certain cancers. mTOR has two subunits, mTORC1 and mTORC2. Also referred to as “mammalian” target of rapamycin.

Rapamycin, the drug for which this pathway is named (and the anti-aging properties of which are the subject of many studies), was discovered in the 1970s and is used as an immunosuppressant in organ donor recipients.

A drug commonly used for the treatment of type 2 diabetes. Metformin is in a class of antihyperglycemic drugs called biguanides. It works by decreasing gluconeogenesis in the liver, reducing the amount of sugar absorbed in the gut, and increasing insulin sensitivity. A growing body of evidence indicates that metformin modulates the aging processes to improve healthspan and extend lifespan. Furthermore, metformin may prevent genomic instability by scavenging reactive oxygen species, increasing the activities of antioxidant enzymes, inhibiting macrophage recruitment and inflammatory responses, and stimulating DNA damage responses and DNA repair.[1]

[1] Najafi, Masoud, et al. "Metformin: Prevention of genomic instability and cancer: A review." Mutation Research/Genetic Toxicology and Environmental Mutagenesis 827 (2018): 1-8.

Tiny organelles inside cells that produce energy in the presence of oxygen. Mitochondria are referred to as the "powerhouses of the cell" because of their role in the production of ATP (adenosine triphosphate). Mitochondria are continuously undergoing a process of self-renewal known as mitophagy in order to repair damage that occurs during their energy-generating activities.

The process by which new mitochondria are made inside cells. Many factors can activate mitochondrial biogenesis including exercise, cold shock, heat shock, fasting, and ketones. Mitochondrial biogenesis is regulated by the transcription factor peroxisome proliferator-activated receptor gamma coactivator 1-alpha, or PGC-1α.

A diet based mainly on foods presumed to be available to paleolithic humans. It includes vegetables, fruits, nuts, roots, meat, and organ meats while excluding foods such as dairy products, grains, refined sugar, legumes, and other processed foods.

Oxygen-containing chemically-reactive molecules generated by oxidative phosphorylation and immune activation. ROS can damage cellular components, including lipids, proteins, mitochondria, and DNA. Examples of ROS include: peroxides, superoxide, hydroxyl radical, and singlet oxygen.

A related byproduct, reactive nitrogen species, is also produced naturally by the immune system. Examples of RNS include nitric oxide, peroxynitrite, and nitrogen dioxide.

The two species are often collectively referred to as ROS/RNS. Preventing and efficiently repairing damage from ROS (oxidative stress) and RNS (nitrosative stress) are among the key challenges our cells face in their fight against diseases of aging, including cancer.

The maximum rate of oxygen consumption as measured during incremental exercise and indicates the aerobic fitness of an individual, and plays a role in endurance capacity during prolonged, submaximal exercise.