Browse the evidence

Dietary fiber interventions in healthy adults do not consistently produce significant increases in total or individual short-chain fatty acid (SCFA) levels, with outcomes strictly dependent on fiber type, dose, and analytical methodology.

Do not assume that taking a generic fiber supplement will automatically boost your short-chain fatty acids. The effect is highly variable and depends on the specific type of fiber (e.g., inulin vs. resistant starch), the dose, and your individual gut microbiome composition. Focus on diverse fiber sources from whole foods rather than expecting a uniform metabolic boost from supplements.

The analytical method used to measure SCFAs (e.g., GC vs. HPLC) significantly influences the detection of statistically significant changes, with GC-based methods on plasma/serum showing more frequent significant changes than HPLC on feces.

When evaluating fiber studies, check the measurement method. Studies using Gas Chromatography (GC) on blood samples are more likely to report significant SCFA changes than those using HPLC on feces, even if the biological effect is similar. This highlights the difficulty in measuring blood SCFAs due to low concentrations.

There is no significant dose-response relationship between the volume, frequency, duration, or pace of running and reduced mortality risk; higher doses do not yield greater benefits than lower doses.

Do not feel pressured to increase your running volume, frequency, or speed to get more health benefits. If you are already running occasionally, you are likely getting the maximum mortality benefit available from running. Focus on consistency rather than intensity or volume.

Inhibition of TXNIP expression or activity improves insulin sensitivity, protects pancreatic beta-cells from apoptosis, and ameliorates metabolic abnormalities in type 2 diabetes and obesity.

Targeting TXNIP is a promising therapeutic strategy for managing Type 2 Diabetes and obesity. Drugs like Metformin, GLP-1 agonists, and potentially repurposed drugs like Verapamil work partly by lowering TXNIP levels. This improves insulin sensitivity and protects pancreatic cells. However, because TXNIP helps maintain blood sugar during fasting, inhibitors must be carefully dosed to avoid hypoglycemia and potential long-term cancer risks associated with its loss.

TXNIP acts as a nutrient sensor in the hypothalamus to regulate energy expenditure and adiposity; its overexpression in Agouti-related protein (AGRP) neurons leads to diet-induced obesity.

Your brain plays a key role in how much you weigh. A protein called TXNIP in your brain acts as a sensor for food intake. When this protein is too high, your body burns less energy and stores more fat. Keeping this protein in check in the brain may help prevent obesity.

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.

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.

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.

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.

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.

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.

LCHF diets may increase mortality risk and cause adverse effects on cardiovascular and gut health due to reduced fiber intake and high fat content.

Be cautious with long-term LCHF diets. They may increase your risk of mortality and harm your gut health due to low fiber. Prioritize a diet rich in fiber and whole grains for long-term cardiovascular and gut health.

Exogenous infusion of sodium-3-hydroxybutyrate (ketone bodies) in healthy humans significantly reduces myocardial glucose uptake and increases myocardial blood flow.

For healthy individuals, raising ketone levels (e.g., through fasting, ketogenic diet, or supplementation) shifts the heart's fuel source from glucose to ketones and increases blood flow to the heart muscle. This metabolic shift may be beneficial for cardiac efficiency and health, particularly in conditions where glucose utilization is impaired or blood flow is restricted.

Lean individuals (BMI < 25 kg/m² for Caucasians, < 23 kg/m² for Asians) with NAFLD face a higher risk of severe liver disease and mortality compared to obese NAFLD patients, challenging the belief that lean NAFLD follows a benign clinical course.

If you have fatty liver but are not overweight, do not assume your condition is mild. You are at higher risk for severe liver complications than obese patients with fatty liver. You require regular monitoring for fibrosis progression and metabolic health, just as strictly as obese patients.

In lean individuals, the PNPLA3 rs738409 G allele is an independent predictor of NAFLD and NASH severity, whereas it is not associated with histological severity in obese patients.

If you are lean and have fatty liver, genetic testing for PNPLA3 may help predict your risk of progression to NASH. This information can guide how frequently you need liver biopsies or advanced imaging, even if you maintain a healthy weight.

As national GDP per capita increases, the prevalence of overweight and obesity shifts from being concentrated in the wealthiest population deciles to the poorest deciles, driven by rising obesity rates among the poor rather than declining rates among the wealthy.

Public health policy in developing nations must anticipate that obesity will increasingly become a disease of poverty, not wealth. Interventions should target the poor, focusing on affordable healthy food access and physical activity opportunities, rather than assuming the wealthy are the primary at-risk group.

Thyroid hormone (T3) accelerates skeletal muscle contraction and relaxation rates by stimulating the expression of fast myosin heavy chain isoforms (MYH2, MYH1, MYH4) and sarcoplasmic reticulum Ca2+ ATPase (SERCA1a).

If you have hypothyroidism, treating it to normal levels may help restore normal muscle speed and function, as thyroid hormone directly controls the proteins responsible for contraction speed. However, for healthy individuals, manipulating thyroid levels is not a standard or safe performance enhancement strategy.

Thyroid hormone (T3) increases skeletal muscle mitochondrial biogenesis, oxidative capacity, and resting metabolic rate by upregulating PGC1α, UCP3, and mitochondrial enzymes.

Normal thyroid function is essential for healthy muscle metabolism and energy production. If you have hypothyroidism, treatment can restore mitochondrial function and energy levels. Do not attempt to increase thyroid levels beyond normal ranges for metabolic boosting, as this can lead to muscle wasting and other health issues.

Thyroid hormone (T3) regulates skeletal muscle myogenesis by controlling intracellular T3 levels via D2 and D3 deiodinases, which determines satellite cell proliferation and differentiation.

Proper thyroid function is necessary for effective muscle repair and regeneration after injury or exercise. If you have thyroid issues, addressing them may improve your body's ability to repair muscle tissue.