Metabolism & Nutrient Sensing

Adiponectin is a hormone your fat cells release (an 'adipokine'), mostly from white fat. It is unusual among fat hormones: it goes DOWN as you gain fat, not up. Levels fall with…

Brown adipose tissue (BAT) is your body's heat-generating fat. It is packed with mitochondria and a protein called UCP1. UCP1 lets the mitochondria release energy as heat instead…

Caloric restriction is a sustained cut in your energy intake. Typically that is 10 to 30% below eating freely (ad libitum), but without malnutrition. It switches on conserved…

A continuous glucose monitor (CGM) is a wearable sensor that tracks your blood sugar around the clock. It usually sits just under your skin and reads interstitial glucose every…

CRON stands for Caloric Restriction with Optimal Nutrition. It is a structured way of eating less. You cut your energy intake by roughly 20 to 30%. At the same time, you…

De novo lipogenesis (DNL) is how your liver turns excess carbs, mainly glucose and fructose, into new fat. The fat is packaged as triglycerides into VLDL particles, or stored as…

Ectopic fat is fat stored in or around organs that normally hold very little of it. Think liver, muscle, pancreas, and heart. It is different from the fat under your skin or…

The fasting-mimicking diet (FMD) is a 5-day plan that is low in calories, low in protein, and plant-based. Valter Longo's group designed it. It copies the metabolic effects of a…

Free fatty acids (NEFA, or non-esterified fatty acids) are long-chain fats floating in your blood. They ride on the protein albumin. They are released when an enzyme…

Glucagon is a hormone (29 amino acids long) made by your pancreas's alpha-cells. It is released when your blood sugar drops, during long fasts, and after you eat protein, and it…

Gluconeogenesis is how your liver (and, in long fasts, your kidney) makes new glucose from non-carb sources. The main precursors are lactate, glycerol, and 'glucogenic' amino…

Glucose variability is how much your blood sugar swings up and down over hours and days. It is measured a few ways. Common ones are the standard deviation, the coefficient of…

HbA1c (glycated hemoglobin) is the share of your hemoglobin that is stably bound to glucose. It gives an integrated picture of your average blood glucose over roughly the past 2…

Hepatic insulin resistance means your liver stops listening to insulin's 'stop making sugar' signal after meals, even though it still obeys insulin's 'make fat' signal.…

HOMA-IR (Homeostatic Model Assessment of Insulin Resistance) is a fasting blood index of insulin resistance. You calculate it as (fasting insulin in µU/mL × fasting glucose in…

The incretin effect is a striking observation: drinking glucose triggers a bigger insulin response than getting the same amount of glucose by IV. The difference comes from gut…

Insulin resistance is when your tissues stop responding well to insulin, so your pancreas has to pump out more to keep blood sugar in check. It is driven by belly fat (visceral…

Insulin sensitivity is how well your cells respond to insulin. The key cells are in muscle, liver, and fat. When insulin works, they take up glucose, and the liver shuts off its…

Intermittent fasting is an umbrella term for eating patterns that alternate normal eating with longer fasting windows. Common forms include 16:8 time-restricted eating,…

The ketogenic diet is a very-low-carb (usually under 50 g a day), high-fat, moderate-protein way of eating that keeps your body in steady ketosis (burning fat for fuel and making…

Ketone bodies are your body's backup fuel for when carbs run low. There are three of them. They are beta-hydroxybutyrate, acetoacetate, and acetone. Your liver makes them inside…

Ketosis is a fuel-switch in your body. When glucose runs low, your liver turns fat into ketone bodies. There are three: beta-hydroxybutyrate (BHB), acetoacetate, and acetone.…

Leptin is a hormone your white fat releases, in proportion to how much fat you carry. It acts on receptors in your hypothalamus (especially the arcuate nucleus) to curb appetite…

MASLD (metabolic dysfunction-associated steatotic liver disease) is the 2023 rename of what used to be called non-alcoholic fatty liver disease (NAFLD). Major liver societies…

Metabolic flexibility is your body's ability to switch fuel sources smoothly. The two main fuels are glucose and fatty acids. You switch between them as you eat, fast, and move.…

Metabolic syndrome is a cluster of linked cardiometabolic risk factors that sharply raise your risk of type 2 diabetes, heart disease, and early death. The most-used criteria…

Postprandial glucose is your blood sugar after a meal. It often peaks within 30 to 90 minutes (around 60 minutes for mixed meals), then drifts back toward your fasting level.…

Prolonged fasting means going without food for roughly 48 hours up to several days. During it, you take only water, electrolytes, and sometimes minimal calories. Once your…

The respiratory exchange ratio (RER) is the ratio of carbon dioxide you produce (VCO₂) to oxygen you consume (VO₂) per unit time. At rest and during moderate aerobic effort, it…

Resting metabolic rate (RMR) is the energy you burn at complete rest, just to keep your core systems running. (It is sometimes used interchangeably with basal metabolic rate, or…

Time-restricted eating (TRE) confines your daily food intake to a consistent window, typically 6 to 10 hours. That leaves 14 to 18 hours of fasting. The concept came from Satchin…

Uncoupling proteins (UCPs) are carriers in your inner mitochondrial membrane that release the proton gradient as heat instead of capturing it as ATP. The best-known is UCP1,…

HOMA-β (Homeostatic Model Assessment of Beta-cell function) is a quick estimate of how well your pancreas makes insulin. It uses just fasting blood values. The formula is (20 ×…

β-oxidation is the main way your mitochondria burn fat for energy. It chops a fatty acid into two-carbon pieces (acetyl-CoA), one cycle at a time. Each cycle runs four steps:…