Browse the evidence

Central insulin signaling regulates hepatic glucose production via the vagus nerve and hepatic IL-6/STAT3 pathway, independent of peripheral insulin levels.

Insulin doesn't just work on your muscles; it also works on your brain to tell your liver to stop making sugar. If your brain is resistant to insulin, your liver may overproduce glucose, contributing to high blood sugar. Strategies that improve overall metabolic health may help restore this central signaling.

Plasma leptin concentrations are not affected by dietary fat content (ranging from 14% to 31% of energy) when body weight and adiposity are held constant.

If you are maintaining your current weight, changing the percentage of fat in your diet (whether you eat 14%, 23%, or 31% of calories from fat) will not change your leptin levels. Leptin is driven by how much body fat you have, not by the specific macronutrient ratio of your food, provided your weight remains stable.

In healthy humans, higher body fat percentage and BMI are directly correlated with increased resting muscle sympathetic nerve activity (MSNA), which in turn is correlated with increased calf vascular resistance.

Higher body fat is linked to higher sympathetic nerve activity, which increases blood vessel resistance. This physiological link helps explain why obesity is a risk factor for hypertension. While you cannot directly 'turn off' this nerve activity, understanding this link highlights why weight management is crucial for cardiovascular health, as reducing fat mass may help normalize sympathetic tone and vascular resistance.

Acute elevation of plasma insulin to levels observed in fasting overweight subjects stimulates sympathetic nerve activity in lean subjects, suggesting hyperinsulinemia contributes to sympathetic activation in obesity.

High insulin levels, even in lean individuals, can trigger increased sympathetic nerve activity. This suggests that insulin resistance and high fasting insulin levels in overweight individuals may be a key driver of the high blood pressure and vascular resistance seen in obesity. Managing insulin levels through diet and lifestyle may help reduce this sympathetic drive.

In obese women, increased adipose tissue 11β-HSD1 activity regenerates cortisol locally, contributing to central obesity and insulin resistance, while impaired hepatic conversion of cortisone to cortisol leads to compensatory HPA axis activation without raising circulating cortisol levels.

For obese women, high body fat is linked to increased activity of an enzyme (11β-HSD1) in fat tissue that converts inactive cortisone into active cortisol locally. This local excess drives insulin resistance and fat accumulation, even if blood cortisol levels appear normal. Future treatments may target this specific enzyme in fat rather than just managing stress or blood cortisol levels.

Chronic glucocorticoid excess causes central fat redistribution and metabolic syndrome features despite acute lipolytic effects, primarily through increased de novo lipogenesis and adipocyte differentiation rather than sustained systemic lipolysis.

If you are on long-term steroid medication or have high chronic cortisol levels, do not expect fat loss from stress-induced lipolysis. Instead, focus on managing insulin levels and caloric intake, as the hormonal environment promotes fat storage in the abdomen and liver through increased synthesis and cell differentiation, not just calorie burning.

Glucocorticoids promote hepatic de novo lipogenesis (DNL) and VLDL secretion, contributing to hepatic steatosis and increased circulating triglycerides in metabolic syndrome.

Managing chronic steroid use or high cortisol is critical for liver health. Reducing glucocorticoid exposure can help lower liver fat production and improve lipid profiles, reducing the risk of fatty liver disease.

In patients with Non-Alcoholic Steatohepatitis (NASH), elevated fecal primary bile acids (cholic acid and chenodeoxycholic acid) and increased hepatic bile acid synthesis correlate with markers of hepatic injury (steatosis, fibrosis, and elevated liver enzymes).

If you have NASH, your liver is producing and excreting higher levels of bile acids, which are directly linked to liver damage. This isn't just about 'fatty liver' from eating too much; it's a specific metabolic signaling issue. Managing this likely requires addressing the underlying metabolic dysregulation rather than just weight loss alone, as bile acid profiles are a key marker of disease severity.

Perilipin (Plin) suppresses basal lipolysis by sequestering the co-activator Abhd5, preventing it from interacting with and activating Adipose Triglyceride Lipase (Atgl).

This research explains how your body regulates fat burning. In a resting state, a protein called Perilipin acts like a lock on your fat cells, holding back the enzyme (Abhd5) needed to break down fat. Hormones released during exercise (via PKA) unlock this system, releasing the enzyme to activate fat breakdown. This highlights why hormonal signals (like those from exercise or fasting) are crucial for mobilizing stored fat, not just caloric intake.

Phosphorylation of Perilipin at specific sites (Ser-492 and Ser-517) by PKA is required to release Abhd5, allowing it to interact with and activate Atgl, thereby stimulating lipolysis.

This research identifies the specific molecular 'switch' (PKA phosphorylation of Perilipin) that turns on fat burning. When hormones signal the body to use energy, this switch releases the enzyme (Abhd5) that activates fat breakdown. This underscores the importance of hormonal triggers (like exercise or fasting) in mobilizing stored fat.

Knockdown of Abhd5 reduces both basal and stimulated lipolysis, indicating that Abhd5 is essential for triglyceride breakdown independent of Hormone-Sensitive Lipase (HSL).

This research shows that Abhd5 is crucial for fat burning, even when other enzymes (HSL) are blocked. This suggests that fat loss is a multi-enzyme process, and targeting only one pathway may not be sufficient for maximum fat mobilization.

Palmitate (a saturated free fatty acid) induces oxidative stress and endoplasmic reticulum (ER) calcium depletion, triggering a vicious cycle of mitochondrial dysfunction and apoptosis that leads to pancreatic beta-cell failure and insulin resistance.

High levels of saturated fats (specifically palmitate) in the blood can overwhelm cellular machinery, causing stress that damages insulin-producing cells and reduces insulin sensitivity. This risk is heightened in people with existing insulin resistance. However, not all fats behave this way; unsaturated fats (like oleate) can mitigate this damage. Managing saturated fat intake and maintaining a healthy weight to lower circulating free fatty acids are key strategies to prevent this cellular stress cycle.

Peripheral administration of the recombinant GLP-1-albumin fusion protein Albugon activates central nervous system (CNS) satiety and gastrointestinal pathways via vagal afferents, despite its large size preventing direct blood-brain barrier crossing.

This research suggests that large, long-acting GLP-1 therapies (like Albugon) can reduce appetite and improve blood sugar even though they are too big to enter the brain directly. Instead, they stimulate nerves in the gut (vagal afferents) that send signals to the brain's satiety centers. This validates the design of long-acting GLP-1 drugs that rely on peripheral signaling to achieve central effects like reduced hunger.

The ER22/23EK polymorphism is associated with a lower risk of dementia, fewer white matter lesions, and significantly better survival rates in the elderly.

If you are elderly and carry the ER22/23EK variant, you have a genetic advantage for longevity and brain health. This variant is linked to lower dementia risk and better survival. Focus on maintaining this advantage through stress management and a healthy lifestyle, as your biology is naturally protected against the negative effects of cortisol on the brain.

Activation of the nuclear receptor FXR in enteroendocrine L-cells inhibits GLP-1 production by suppressing glycolysis and proglucagon transcription, whereas FXR deactivation (via deficiency or bile acid sequestrants) increases GLP-1 and improves glucose tolerance.

This research highlights that the specific bile acid receptor targeted matters for glucose control. While TGR5 agonists increase GLP-1, FXR activation suppresses it. Therefore, therapies aiming to boost GLP-1 (like bile acid sequestrants) work partly by deactivating FXR, not just by activating TGR5. This suggests that optimal treatments might combine TGR5 activation with FXR inhibition to maximize GLP-1 production.

Oral conjugated estrogen (0.625 mg/day) and combined oral estrogen/progestin (0.625 mg estrogen + 2.5 mg medroxyprogesterone acetate) significantly reduce plasma PAI-1 levels by approximately 50% in postmenopausal women, thereby enhancing systemic fibrinolysis.

For postmenopausal women, oral hormone replacement therapy (specifically conjugated estrogen) significantly lowers PAI-1, a protein that inhibits blood clot breakdown, by about half. This suggests oral estrogen may improve the body's ability to dissolve clots. However, transdermal (patch) estrogen does not appear to have this effect, and the net cardiovascular benefit is uncertain because oral estrogen might also increase other clotting risks in some women. This is not a standalone treatment for heart disease prevention without considering individual risk factors.

Oral conjugated estrogen therapy enhances systemic fibrinolysis, as evidenced by increased D-dimer levels, which correlates inversely with the reduction in PAI-1 levels.

When oral estrogen lowers PAI-1, it functionally increases the breakdown of blood clots (fibrinolysis), shown by higher D-dimer levels. This suggests oral estrogen may help prevent clot-related cardiovascular events by keeping the blood's clot-dissolving system active.

Transdermal estradiol (0.1 mg/day) does not significantly alter PAI-1 levels or enhance fibrinolysis in postmenopausal women, unlike oral estrogen.

If you use estrogen patches (transdermal), you likely will not get the fibrinolytic (clot-dissolving) benefits seen with oral estrogen pills. The patch does not significantly change PAI-1 levels.

Long-term athletic training and the resulting lower lifetime estrogen exposure significantly reduce the risk of breast and reproductive system cancers in women.

Starting athletic training early in life (high school or earlier) and maintaining it through college can significantly lower your lifetime risk of breast and reproductive cancers. This benefit is likely due to lower lifetime estrogen exposure associated with lower body fat levels.

The effect of maternal hyperglycemia on childhood adiposity (overweight/obesity and sum of skinfold thickness) is sex-specific, being significant in girls but not in boys.

For girls exposed to maternal hyperglycemia in utero, parents should be particularly vigilant about monitoring weight and body composition, as they are at higher risk for childhood obesity and adiposity compared to boys. Regular check-ups focusing on growth charts and body fat percentage are recommended for these girls.

Increased abundance of specific Firmicutes taxa (e.g., Ruminococcus gnavus, Lachnospiraceae) and Proteobacteria (e.g., Escherichia, Enterobacteriaceae) in obesity contributes to chronic low-grade inflammation and metabolic endotoxemia via LPS production and mucin degradation.

Obesity is linked to an increase in bacteria that produce lipopolysaccharides (LPS), which can leak into the bloodstream and cause chronic inflammation. This inflammation is fueled by a diet low in fiber and high in saturated fats. Prioritize fiber-rich foods (vegetables, legumes, whole grains) to support bacteria that maintain gut barrier integrity and reduce inflammation.

The FABP2 Thr54 genetic polymorphism increases intestinal fatty acid binding affinity, leading to higher fat oxidation rates and subsequent insulin resistance.

If you carry the FABP2 Thr54 gene variant, your body is genetically predisposed to process dietary fats in a way that promotes insulin resistance. This risk is significantly amplified by a diet high in saturated fats. Managing this involves prioritizing a diet lower in saturated fats to mitigate the increased fat oxidation and insulin resistance associated with this specific genetic profile.

The increased risk of IGT and T2DM in PCOS is significantly modified by ethnicity, with Asian and American populations showing higher odds ratios than European populations, and this risk persists even when BMI is matched.

Your ethnicity matters for your diabetes risk with PCOS. Asian and Hispanic/Latina women with PCOS face a higher risk than white women, even if they are the same weight. This means you may need more aggressive screening or lifestyle interventions regardless of your BMI.

Chronic metabolic acidosis induced by ammonium chloride administration decreases albumin synthesis and induces negative nitrogen balance in humans.

Sustained metabolic acidosis, even without kidney disease, can significantly slow down your body's production of albumin and lead to muscle loss. This suggests that managing acid-base balance is crucial for muscle preservation, potentially through dietary strategies that mitigate acid load.