Browse the evidence

Bariatric surgery (specifically gastric bypass) leads to elevated levels of GLP-1 and PYY, which are linked to enhanced delivery of nutrients to the distal intestine and underlie beneficial outcomes on weight loss and glycemia.

Bariatric surgery works partly by changing how your gut senses food, leading to higher levels of satiety hormones like GLP-1 and PYY, which help with weight loss and blood sugar control.

In heart failure with reduced ejection fraction (HFrEF), higher adiposity measured by waist-to-height ratio is associated with a significantly higher risk of heart failure hospitalization, and the 'obesity-survival paradox' (where higher BMI appeared protective) is eliminated when adjusting for natriuretic peptides and other prognostic variables.

For patients with heart failure and reduced ejection fraction, relying on BMI to assess risk is misleading. Higher waist-to-height ratio (indicating central adiposity) is linked to a significantly higher risk of hospitalization. The idea that being 'overweight' is protective in heart failure is a statistical artifact; once you account for fluid retention and biomarkers like natriuretic peptides, higher adiposity clearly increases risk. Focus on healthy body composition rather than just scale weight.

Subcutaneous adipose tissue, particularly in the gluteal-femoral region, acts as a metabolically protective 'sink' for lipids, preventing ectopic deposition in vital organs.

Building lower-body muscle and promoting subcutaneous fat storage in the legs and hips can protect against metabolic disease by acting as a safe storage site for excess lipids, preventing them from damaging the liver and muscles.

Increasing whole-grain intake to 60-120g/day for 16 weeks in overweight, low-consumer adults does not significantly improve cardiovascular disease risk markers (LDL, blood pressure, inflammation, insulin sensitivity) compared to a control diet.

If you are overweight and rarely eat whole grains, switching to 60-120g of whole grains daily for 4 months is unlikely to improve your cholesterol, blood pressure, or inflammation markers on its own. Public health messages may need to clarify that whole grains are part of a broader healthy lifestyle, not a magic bullet for CVD risk in this population.

Systemically administered GABAA receptor agonistic modulators (barbiturates, benzodiazepines, zolpidem, zopiclone, neuroactive steroids) reduce sleep latency, increase NREM sleep continuity, and promote sleep spindles, but suppress slow-wave activity (SWA) and REM sleep.

GABAA-targeting sleep medications (like benzodiazepines or Z-drugs) generally help you fall asleep faster and stay asleep longer by increasing NREM sleep and spindles. However, they tend to reduce deep slow-wave sleep and REM sleep. If sleep quality (depth and dreaming) is your priority, these drugs may alter your sleep architecture in ways that feel less restorative despite longer duration.

Selective GABAA agonists (muscimol, THIP) increase NREM sleep continuity and slow-wave activity (SWA) while attenuating spindle activity, suggesting a different physiological role for tonic vs phasic GABA receptor activation.

Unlike standard sleep aids that suppress deep sleep, direct GABAA agonists (like THIP) may increase deep slow-wave sleep and sleep continuity without necessarily speeding up sleep onset. This suggests that the *type* of GABA receptor activation (tonic vs phasic) dictates whether you get deep sleep or just sedation.

Higher plasma levels of branched-chain amino acids (isoleucine, valine, leucine) are causally associated with an increased risk of type 2 diabetes.

Monitor plasma amino acid levels if you have metabolic risk factors. High levels may signal insulin resistance.

Higher educational attainment is causally associated with a decreased risk of type 2 diabetes.

Education is a powerful protective factor for metabolic health. Public health policies should focus on educational access.

Higher baseline levels of Interleukin-6 (IL-6) and a steeper longitudinal increase in IL-6 levels are independently associated with an accelerated rate of developing multimorbidity (accumulation of chronic diseases) in older adults.

If you are over 60, monitoring inflammatory markers like IL-6 may help predict your risk of developing multiple chronic conditions. High or rising IL-6 levels are linked to a faster accumulation of diseases. This suggests that managing inflammation could be a key strategy to slow down the progression of multimorbidity in older adults.

Low levels of Dehydroepiandrosterone sulfate (DHEAS) are associated with a higher cross-sectional burden of multimorbidity in older adults.

Low levels of the hormone DHEAS are linked to having more chronic diseases in older adults. While not as strong a predictor of future disease progression as IL-6, low DHEAS is a marker of hormonal dysregulation associated with a higher burden of illness.

Obesity-induced infiltration of M1 macrophages into metabolic tissues (adipose, liver, muscle) drives chronic inflammation that directly causes insulin resistance by interfering with insulin signaling pathways.

For those with obesity, reducing the inflammatory burden on metabolic tissues is key. This involves strategies that reduce macrophage infiltration, such as weight loss and potentially anti-inflammatory dietary patterns, to improve insulin sensitivity.

Specific inflammatory pathways (JNK, IKK/NF-κB, JAK/STAT) activated by macrophage-derived cytokines (TNF-α, IL-6, IL-1β) directly impair insulin signaling by causing serine phosphorylation of IRS-1.

Understanding that inflammation directly blocks insulin action at the cellular level highlights why anti-inflammatory strategies (like weight loss) are effective for improving insulin sensitivity.

High-intensity exercise (>75% VO2max) limits fat oxidation due to a depletion of free carnitine, which is consumed to buffer excess acetyl-CoA from glycolysis, thereby restricting fatty acid transport into the mitochondria.

Avoid high-intensity exercise if your primary goal is to maximize fat oxidation per minute. At intensities above 75% VO2max, your body prioritizes carbohydrates, and a lack of free carnitine prevents fat from being used as fuel. Stick to moderate intensities for better fat burning efficiency.

Elevated local glucocorticoid activity in adipose tissue, driven by increased 11beta-HSD1 enzyme expression, causes visceral obesity and metabolic syndrome features despite normal circulating cortisol levels.

Visceral obesity is driven by local enzyme activity (11beta-HSD1) converting inactive steroids into active cortisol within belly fat, not necessarily by high blood cortisol. This suggests that therapies targeting this specific enzyme in adipose tissue could treat metabolic syndrome and visceral obesity without affecting systemic hormone levels.

Genetic predisposition for higher leisure screen time (LST) and lower moderate-to-vigorous physical activity (MVPA) causally increases body mass index (BMI) and adiposity, and these protective effects of physical activity on disease risk are mediated or confounded by BMI.

This research suggests that the health benefits of reducing sedentary time and increasing physical activity are largely achieved through their effect on body weight and fat. To prevent diseases like type 2 diabetes and heart disease, managing body mass index is likely a key mechanism through which physical activity works.

Dietary restriction (caloric or nutrient restriction) extends lifespan by inactivating the TOR (Target of Rapamycin) pathway, which subsequently influences DAF-16/FOXO activity and mRNA levels.

Dietary restriction, such as caloric restriction, extends lifespan in model organisms by suppressing the TOR pathway. This suppression allows for the activation of DAF-16/FOXO, which regulates genes involved in longevity. This suggests that nutrient sensing is a critical lever for aging.

Activation of the AMP-activated protein kinase (AMPK) pathway extends lifespan and stress resistance by directly phosphorylating and activating DAF-16/FOXO.

AMPK, an energy sensor, extends lifespan by directly activating the DAF-16/FOXO transcription factor. This mechanism links cellular energy status (low glucose/high AMP) to longevity pathways.

Genetic variants in the FTO gene (specifically rs17817449 and rs1421085) are significantly associated with increased adiposity (BMI, weight, waist circumference) and insulin resistance, but these metabolic effects are mediated entirely by the increase in body fat rather than direct metabolic dysfunction.

If you have a family history of obesity, you likely carry genetic variants (like FTO) that make you prone to storing more fat. This doesn't mean you are powerless, but it does mean you may need to be more vigilant about energy balance than someone without these variants. Focus on maintaining a healthy body weight, as your genetic risk manifests primarily through increased adiposity rather than direct metabolic defects.

BMI is a suboptimal tool for predicting chronic disease risk and diagnosing obesity because it fails to distinguish between fat mass and muscle mass, leading to misclassification of athletes and elderly individuals.

Do not rely on BMI alone to determine your health status, especially if you are an athlete or elderly. BMI cannot distinguish between muscle and fat. Use waist circumference or body composition analysis for a more accurate assessment of obesity and health risk.

Infection and immune response actively alter sleep patterns, typically increasing slow-wave sleep (SWS) and decreasing REM sleep, which may be an adaptive mechanism to conserve energy for the immune response.

If you are sick, expect your sleep to change (more deep sleep, less REM). This is a normal, adaptive response by your body to fight the infection. Do not fight this sleepiness; allow your body to rest and recover.

A panel of biomarkers including physical capability (grip strength, walking speed), physiological function (blood pressure, glucose), cognitive function (executive function, processing speed), and inflammatory markers (IL-6, TNF-alpha) serves as valid surrogate endpoints for assessing healthy ageing and predicting mortality.

To track your biological health, focus on measurable functional outputs rather than just your birth year. Regularly monitor your grip strength, walking speed, blood pressure, and fasting glucose. These are established, accessible indicators that predict mortality and functional decline better than age alone. If you are maintaining or improving these metrics, you are likely ageing healthily.

There is no convincing evidence of an association between the food environment (e.g., availability of supermarkets, fast-food outlets) and T2DM risk or prevalence.

Current evidence does not strongly support the idea that changing the food environment (e.g., adding supermarkets or removing fast food) will significantly reduce the risk of type 2 diabetes. Other factors, such as urbanization and walkability, may be more influential.

Central administration of GLP-1 receptor agonists (GLP-1(7-36) amide or exendin-4) inhibits food and water intake in rats via hypothalamic glucose-sensing mechanisms, whereas peripheral administration has no acute effect on intake.

Central GLP-1 signaling strongly suppresses food and water intake in rats, while peripheral signaling does not. This suggests that for appetite suppression, the route of delivery and central receptor engagement are critical.

Genetic susceptibility interacts with environmental factors to influence obesity risk, where specific gene variants (e.g., beta-3 adrenergic receptor, UCP-1) affect energy expenditure and fat oxidation, but these genes only contribute to obesity when triggered by energy-dense diets and sedentary behavior.

If you have a family history of obesity, you may have genetic variants that make you more sensitive to high-calorie foods and inactivity. This doesn't mean you are doomed, but it means you need to be more vigilant about your diet and physical activity levels than someone without those genetic risks.