Browse the evidence

Ingestion of short-chain fatty acids (SCFAs), specifically propionate and butyrate, stimulates PYY gene expression and secretion in human enteroendocrine cells via histone deacetylase (HDAC) inhibition, thereby increasing plasma PYY levels.

To maximize your natural PYY production (a hormone that helps you feel full), focus on consuming high-fiber foods that your gut bacteria can ferment into short-chain fatty acids like butyrate and propionate. This process naturally stimulates your gut hormones to regulate appetite, a mechanism that works specifically in humans.

Direct activation of GLP-1 receptors in the ventral tegmental area (VTA) and nucleus accumbens (NAc) core reduces the intake of highly-palatable foods (sucrose and high-fat diet) and body weight, mediated by direct projections from NTS GLP-1 neurons.

This research suggests that GLP-1 medications (like semaglutide or liraglutide) work partly by targeting the brain's reward system (VTA and Nucleus Accumbens) rather than just signaling fullness to the stomach. By dampening the reward signal associated with highly palatable, high-fat, or sugary foods, these drugs reduce the motivation to eat them. This explains why users often find themselves losing interest in junk food specifically, rather than just feeling physically stuffed.

Endogenous GLP-1 signaling in the VTA and NAc core is physiologically necessary to regulate high-fat diet intake, as blocking these receptors leads to increased consumption.

Your brain naturally produces GLP-1 to help keep you from overeating high-fat foods. This study shows that if you block this natural signaling in the reward centers of your brain, you will eat more high-fat food. This suggests that maintaining healthy endogenous GLP-1 signaling (through diet and lifestyle) is important for regulating cravings for palatable foods.

Training primary care practitioners in patient-centred care improves patient communication, treatment satisfaction, and psychological wellbeing, but is associated with higher body mass index and triglyceride levels compared to routine care.

If you are a clinician, training in patient-centred communication will likely make your patients happier and feel better understood, but be aware that this approach alone may not improve—and might even worsen—weight and triglyceride levels if it replaces active behavioral negotiation. You must explicitly balance listening with directing to prevent adverse metabolic outcomes.

Increasing voluntary exercise in humans often fails to increase total daily energy expenditure (DEE) because it triggers a compensatory reduction in spontaneous physical activity (SPA/NEAT), particularly in older adults.

If you are an older adult, adding structured exercise might not increase your total daily calorie burn because your body may automatically reduce your spontaneous movements (like fidgeting or pacing) to compensate. To maximize energy expenditure, focus on maintaining high spontaneous activity throughout the day rather than relying solely on structured workouts to drive weight loss.

In laboratory rodents, access to running wheels increases food consumption and reduces body fat, but does not fully compensate for the energy cost of running through reductions in other spontaneous activities.

This node describes rodent physiology. It suggests that voluntary exercise can drive fat loss even if appetite increases, provided the exercise cost isn't fully offset by reduced other movements. This highlights the importance of measuring total energy expenditure, not just exercise calories.

Activation of AMP-activated protein kinase (AMPK) increases skeletal muscle GLUT4 gene expression by phosphorylating the transcriptional repressor HDAC5 at serines 259 and 498, causing its nuclear export and relieving transcriptional repression.

Skeletal muscle adapts to energy stress (like exercise) by activating AMPK, which physically removes roadblocks (HDAC5) from the DNA, allowing the body to produce more GLUT4 transporters. This is a fundamental biological mechanism for improving insulin sensitivity and glucose handling in muscle tissue.

Higher pericardial fat volume is independently associated with prevalent atrial fibrillation, even after adjusting for body mass index and other cardiovascular risk factors.

Maintaining a healthy weight helps reduce pericardial fat, which is linked to a higher risk of atrial fibrillation. While BMI is a common metric, this research suggests that the fat specifically surrounding the heart is a critical factor. If you have atrial fibrillation or risk factors for it, discussing cardiac imaging or weight management strategies with your cardiologist may be beneficial, as reducing this specific fat deposit could potentially lower AF risk.

Exercise training reduces the exercise-induced activation of AMPK in skeletal muscle, primarily due to a significant decrease (10-60%) in AMPKgamma3 protein content and potentially elevated glycogen levels.

As you become fitter, your muscle's acute AMPK response to the same workout will decrease. This is not a failure; it indicates improved energy homeostasis and efficiency. This reduction is largely driven by a 10-60% drop in AMPKgamma3 protein content. Do not interpret this reduced molecular signaling as a lack of training effect.

Pharmacological activation of AMPK in skeletal muscle promotes glucose transport and fatty acid oxidation while suppressing glycogen synthase activity and protein synthesis.

Activating AMPK (through exercise or certain drugs) shifts your muscle metabolism to burn fuel (glucose and fat) and store less glycogen, while simultaneously pausing muscle building (protein synthesis). This is why timing nutrition around workouts is critical: you need to manage the trade-off between burning fuel and building muscle.

Cellular senescence contributes to organismal aging through two main pathways: depleting tissue self-renewal capacity and disrupting tissue structure/function via inflammatory secretions.

Understand that 'zombie cells' (senescent cells) accumulate with age and actively harm tissue by releasing inflammatory signals and stopping stem cells from working. Strategies that reduce senescence or clear these cells (senolytics) are an area of active research for promoting healthy aging.

GrimAge epigenetic age acceleration (GrimAgeAA) is a superior predictor of age-related clinical phenotypes and all-cause mortality compared to first-generation (Horvath, Hannum) and second-generation (PhenoAge) epigenetic clocks, remaining significant after adjusting for socioeconomic and lifestyle factors.

Use GrimAge epigenetic testing as a high-fidelity biomarker to assess your biological aging risk. Unlike standard age, GrimAge accounts for lifestyle and environmental impacts. A high GrimAgeAA score indicates a significantly higher risk of mortality and functional decline (e.g., frailty, slower walking speed). This information should be used to intensify preventive health measures, such as optimizing cardiovascular health, managing smoking status, and maintaining physical activity, rather than as a deterministic prediction of fate.

Current ISS exercise countermeasures (aerobic and resistance) are insufficient to prevent significant calf muscle atrophy, loss of force-generating capacity, and slow-to-fast fiber type transitions during 6-month spaceflight.

For Earth-based training, this highlights that 'exercise' is not a monolith; the specific type, intensity, and loading profile matter. If you are not seeing muscle maintenance or growth despite regular activity, evaluate if your current routine provides sufficient mechanical tension (especially resistance) to counteract unloading or detraining effects. Standard aerobic exercise alone is insufficient for preserving muscle mass.

Long-duration spaceflight induces a slow-to-fast myosin heavy chain (MHC) transition in both gastrocnemius and soleus muscles, characterized by a decrease in MHC I fibers and an increase in hybrid MHC I/IIa fibers.

Muscle fiber type is plastic. Prolonged inactivity or unloading shifts muscles toward faster, less fatigue-resistant phenotypes. Recovery requires specific retraining to restore slow-twitch characteristics.

Obesity induces a state of chronic low-grade systemic inflammation driven by adipose tissue macrophage infiltration and pro-inflammatory cytokine release (TNF-α, IL-6, IL-1β), which contributes to insulin resistance and metabolic disease.

Obesity is not just about weight; it triggers a biological inflammatory response that harms metabolic health. Managing weight through diet and exercise can reduce this inflammation and lower the risk of diseases like diabetes and heart disease.

Larger hip circumference is associated with a decreased risk of coronary heart disease, independent of waist circumference and BMI, suggesting a protective metabolic effect of peripheral adiposity.

A larger hip circumference relative to your waist may be protective against heart disease. This suggests that storing fat in the hips and thighs might be metabolically healthier than storing it in the abdomen. Focus on reducing abdominal fat rather than just overall weight.

In nonmetastatic colorectal cancer patients, the co-occurrence of systemic inflammation (elevated neutrophil-to-lymphocyte ratio ≥3) and sarcopenia (low skeletal muscle index) doubles the risk of overall and cancer-specific mortality compared to having neither condition.

If you have early-stage colorectal cancer, ask your care team to check your muscle mass (via CT scan) and inflammation markers (blood test) early on. Having both low muscle and high inflammation significantly increases your risk of death, but because these factors are modifiable, identifying them opens the door for interventions like resistance training and nutritional support to potentially improve your survival chances.

Evening exposure to blue-enriched light (peak sensitivity ~460-477 nm) suppresses melatonin secretion and shifts circadian phase, with effects occurring rapidly and recovering quickly upon cessation.

If you are sensitive to sleep disruption, minimize exposure to bright, blue-rich light (LEDs, screens) in the 2 hours before bed. Even low levels (5-10 lux) can trigger circadian responses. If you must use light, choose warmer colors (longer wavelengths >600nm) and keep intensity low. Note that effects reverse quickly once the light is off.

Frequent use of hypnotics and/or tranquilizers (≥60 days/year) is associated with a significantly increased risk of mortality, independent of sleep duration.

If you rely on sleeping pills frequently (more than 60 days a year), be aware that this is linked to a higher risk of death. Discuss alternatives with your doctor, as frequent use may pose long-term health risks.

Caloric restriction extends life span in model organisms by inducing autophagy, a process essential for clearing damaged organelles and proteins.

Caloric restriction extends life in animals by triggering autophagy, which cleans out damaged cellular parts. While strict dieting is hard to maintain, the paper suggests that pharmacologic agents like rapamycin or spermidine might mimic these benefits by inducing autophagy without the discomfort of starvation. Future research aims to identify safe drugs that activate this recycling process.

Pharmacologic induction of autophagy using rapamycin, resveratrol, or spermidine extends life span in model organisms by mimicking caloric restriction.

Drugs like rapamycin and supplements like spermidine can extend life in animals by triggering cellular cleanup (autophagy). However, rapamycin has significant side effects in mice, and resveratrol's benefits in humans are unclear. Current research aims to find safer drugs that activate this process without the negative health impacts.

Aging causes a chronic, low-grade inflammatory state (inflammaging) driven by senescent cells and immune dysregulation, which impairs vaccine efficacy and increases susceptibility to infection.

As you age, your immune system naturally shifts into a state of chronic, low-grade inflammation (inflammaging) due to the accumulation of senescent cells and altered immune signaling. This state reduces your ability to respond effectively to vaccines and increases infection risk. While you cannot stop aging, maintaining a lean body mass and regular exercise can help reduce the burden of senescent cells and lower pro-inflammatory cytokine levels, potentially preserving some immune function.

The accumulation of senescent cells contributes to inflammaging through the Senescence-Associated Secretory Phenotype (SASP), which releases pro-inflammatory cytokines and chemokines.

Senescent cells, which are 'zombie' cells that stop dividing but don't die, secrete inflammatory signals (SASP) that damage surrounding tissue and drive chronic inflammation. This process is a major driver of age-related decline.

Thymic involution with age leads to a reduced output of naive T cells, resulting in a narrowed T-cell receptor repertoire and impaired ability to mount new immune responses to novel antigens.

As you age, your thymus gland shrinks (involution), producing fewer new naive T cells. This means your immune system has a harder time recognizing and fighting new infections or responding to new vaccines because it lacks the diverse 'tools' (naive T cells) to handle novel threats.