Browse the evidence

Caffeine improves endurance performance only in individuals with the CYP1A2 AA genotype (fast metabolizers), while impairing performance in those with the CC genotype.

If you use caffeine for performance, know your CYP1A2 genotype. If you are a 'fast metabolizer' (AA), standard doses (2-4 mg/kg) likely boost your endurance. If you are a 'slow metabolizer' (CC), caffeine may actually hurt your performance and increase health risks like hypertension. If you are intermediate (AC), you likely see no benefit. Genetic testing can prevent wasted effort or performance loss.

The metabolic response (specifically butyrate vs. propionate production) to dietary fiber supplementation is determined by the donor's baseline microbiota composition (Bacteroidaceae-Ruminococcaceae vs. Prevotellaceae-Ruminococcaceae dominance) rather than the specific type of fiber consumed.

Prebiotic fibers do not work in a vacuum; your existing gut bacteria dictate the health benefits you get. If your microbiome is dominated by Bacteroidaceae, fibers like inulin or beta-glucan will likely boost butyrate. If dominated by Prevotellaceae, they will likely boost propionate. There is no single 'best' fiber for everyone; the effect is personalized by your baseline microbiome.

Adherence to the DASH diet is inversely associated with all-cause, cardiovascular disease (CVD), stroke, and cancer mortality, with risk reduction increasing at higher adherence levels.

To lower your risk of dying from heart disease, stroke, or cancer, consistently follow the DASH diet principles. Focus on eating more whole grains, fruits, vegetables, nuts, and low-fat dairy, while cutting back on sodium, red meat, and sugar. Even modest adherence helps, but higher adherence (scoring above 20/40) provides even greater protection.

Longitudinal sleep trajectories characterized by consistently short sleep (<5 hours) or decreasing sleep duration are associated with significantly increased risks of cardiovascular events and all-cause mortality compared to stable normal sleep (7-8 hours).

Monitor your sleep duration over time, not just on a single night. If you consistently sleep less than 5 hours a night, or if your sleep duration is steadily decreasing over months or years, you are at a significantly higher risk for heart disease and early death. Aim for a stable 7-8 hours of sleep. If you are experiencing a decline in sleep, investigate underlying causes (stress, health issues) and seek medical advice, as this pattern is a strong predictor of adverse health outcomes.

Skeletal muscle mass measured via D3-creatine dilution is a strong predictor of functional capacity, mobility limitations, and injurious falls in older adults, whereas lean body mass measured by DXA is only weakly or not associated with these outcomes.

If you are assessing muscle health in older adults, standard DXA scans may underestimate the risk of falls and disability because they include non-muscle tissue in 'lean mass'. Accurate assessment of functional muscle mass (via D3-creatine dilution in research settings) reveals that muscle mass is a critical driver of mobility. For clinical practice, this implies that relying solely on DXA lean mass may miss high-risk individuals who have low functional muscle mass despite normal lean mass readings.

The joint use of Body Mass Index (BMI) and A Body Shape Index (ABSI) provides a significantly better assessment of cardio-metabolic risk factors (high triglycerides, low HDL, high fasting glucose) and visceral adipose tissue (VAT) thickness than using BMI alone.

If you are assessing metabolic health, do not rely on BMI alone. Calculate your A Body Shape Index (ABSI) using your waist circumference, height, and weight. Using both BMI and ABSI together provides a much more accurate picture of your risk for high triglycerides, low HDL, and high blood sugar than BMI by itself. This is especially important if you have a 'normal' BMI but carry weight around your midsection.

Native inulin supplementation (16g/day) combined with dietary advice to consume inulin-rich vegetables promotes greater weight loss and metabolic improvements in obese patients compared to placebo, but this efficacy is significantly compromised by concurrent metformin treatment.

If you are obese and not taking metformin, adding 16g of native inulin daily (starting with 8g for the first week) along with eating more inulin-rich vegetables (like garlic, onions, and artichokes) and eating 30% fewer calories can help you lose more weight and improve metabolic markers than just dieting alone. However, if you are already taking metformin, this specific supplement may not offer the same benefits, so discuss this with your doctor before starting.

Plant-based meat alternatives (PBMAs) often have higher sodium and saturated fat content than conventional meat, and their health benefits are largely inferred from traditional plant-based diets rather than direct evidence on the processed products themselves.

If you are switching to plant-based meats for health, read the label. They often have much more sodium than regular meat. For better health outcomes, prioritize whole plant proteins like beans, lentils, and tofu over highly processed meat alternatives.

Substituting animal meat with plant-based meat alternatives (PBMAs) may improve cardiovascular risk factors like TMAO levels, but may also negatively impact bone health markers compared to meat consumption.

If you switch to plant-based meats, monitor your overall diet. While it might help some heart health markers, it may not support bone health as well as meat. Ensure you are getting enough calcium and vitamin D from other sources.

Higher velocity loss thresholds (20% and 40%) during resistance training maximize muscle hypertrophy compared to lower thresholds (0% and 10%), but excessive velocity loss (40%) induces negative neuromuscular adaptations such as slowed contraction delay and reduced early rate of force development.

For muscle growth, stop your sets when your bar speed drops by about 20% from your fastest rep. This gives you the best hypertrophy benefits without slowing down your muscle's ability to produce force quickly. Avoid stopping sets when speed drops by 40%, as this can hurt your power output. For strength, any moderate velocity loss (10-20%) works well, so prioritize technique and speed over total volume.

Monitoring accumulated training and match load in football is essential for controlling training demands, optimizing physiological adaptations, and guiding individual athlete performance, yet no consensus exists on the most effective monitoring system or metrics.

Track both external load (distance, speed zones via GPS) and internal load (heart rate, sRPE) across the entire week, not just match days. Since there is no single 'best' metric, consistency in how you measure load week-to-week is more important than the specific device used. Focus on the cumulative effect of training sessions, which make up 80% of the weekly load, to guide individual performance.

Saturated fatty acids (SFAs) promote inflammation and insulin resistance by activating the NLRP3 inflammasome and NF-κB pathways, whereas unsaturated fatty acids (UFAs) like EPA/DHA can inhibit these pathways.

The type of fat you eat matters for inflammation. Saturated fats (like palmitate) can trigger inflammatory pathways (NLRP3) and worsen insulin resistance. In contrast, unsaturated fats, particularly omega-3s (EPA/DHA), can help prevent this inflammation. Prioritize unsaturated fats for metabolic health.

Dietary supplements are generally safe and pose significantly lower risks of adverse events, hospitalizations, and fatalities compared to prescription drugs and even common foods.

You do not need to fear that taking a standard dietary supplement will cause you to end up in the emergency room or suffer a fatal outcome. The data shows that serious adverse events from supplements are extremely rare compared to prescription medications and even foodborne illnesses. However, you should still choose products from reputable manufacturers that undergo third-party testing (like NSF or Informed Choice) to ensure purity and avoid adulterated products.

Global dietary quality, measured by the Alternative Healthy Eating Index (AHEI), is modest (mean score 40.3/100) and has improved only slightly (+1.5 points) globally between 1990 and 2018, with significant regional disparities where South Asia and Sub-Saharan Africa saw no improvement or decline.

Your overall diet matters more than any single food. Globally, average diet quality is low (40/100). To improve, focus on increasing fruits, vegetables, whole grains, and healthy fats while reducing sugar-sweetened beverages, red/processed meat, and sodium. This applies to everyone, but the specific gaps vary by region and education level. In many areas, simply increasing produce intake yields the biggest health return.

Macroscopic increases in muscle size (hypertrophy) do not necessarily reflect proportional increases in contractile (myofibrillar) protein; instead, they often result from sarcoplasmic expansion (fluid, glycogen, non-contractile proteins), leading to a dilution of myofibrillar protein concentration.

When you see muscle size increase, do not automatically assume it is all 'quality' contractile tissue. A significant portion of early or even chronic hypertrophy can be 'sarcoplasmic'—driven by fluid, glycogen, and non-contractile proteins. This means your strength-to-size ratio might not improve as much as your tape measure suggests. Focus on strength metrics and protein synthesis markers, not just visual size, to gauge true contractile adaptation.

Individuals with Medicare, dual-eligible insurance, lower education, older age, and male sex bear the highest annual diet-related CMD costs.

Targeted interventions for older adults, men, those with lower education, and those with public insurance (Medicare/dual-eligible) could yield significant cost savings. Focus on increasing nuts, seeds, and seafood omega-3s, and reducing processed meats, sodium, and SSBs.

Unilateral immobilization or unloading causes profound muscle atrophy and metabolic risk factors in the immobilized limb, but these adaptations are specific to that limb and do not transfer to the non-immobilized control limb.

If you have to immobilize one limb (e.g., in a cast), expect that specific limb to lose muscle mass and strength, but know that your other limb will remain healthy and strong. This local specificity means you can maintain overall body function and use the healthy limb to support yourself without risking systemic decline.

Enhanced Negative Work-based Training (ENT) does not significantly improve linear sprinting ability (10m and 30m) in semi-professional soccer players during the in-season period.

Do not rely on a single weekly flywheel session to improve your straight-line speed during the season. While it helps with change of direction and injury prevention, it does not significantly impact 10m or 30m sprint times in semi-professional players. Focus on specific speed training for linear sprinting.

In individuals with incident type 2 diabetes, higher pre-diagnosis BMI is positively associated with an increased risk of microvascular complications (kidney disease and neuropathy), but not macrovascular complications.

For someone with newly diagnosed Type 2 Diabetes, maintaining a healthy pre-diagnosis BMI is crucial for preventing kidney and nerve damage. While weight loss after diagnosis shows benefits, the baseline weight status before diagnosis significantly impacts long-term microvascular risk. Focus on preventing weight gain and managing metabolic health markers.

Short-term resistance exercise (3 bouts over 9 days) combined with a high-fat diet does not prevent the high-fat diet-induced upregulation of immune and inflammatory genes in skeletal muscle, although it does remodel genes associated with muscle growth and structure.

If you are eating a high-fat, low-carb diet, doing resistance exercise for just a few days will not stop your muscles from turning on inflammatory genes. While exercise does build muscle structure genes, it doesn't stop the inflammation caused by the diet. You likely need longer-term training to see protective effects, but don't assume a few workouts cancel out the dietary stress.

In patients with new-onset type 2 diabetes, a weight loss of 10% or more within the first two years is associated with the highest risk of all-cause mortality.

If you have recently been diagnosed with type 2 diabetes, avoid losing more than 10% of your body weight in the first two years. Significant weight loss in this context is linked to higher mortality, possibly due to muscle loss or other health issues. Focus on maintaining a stable weight rather than aggressive weight loss.

Food industry sponsorship of academic research systematically biases the research agenda toward physical activity and nutrient-specific interventions, thereby diverting attention from the health impacts of highly processed foods and ultra-processed diets.

When evaluating health advice or research, always check the funding source. If a study on obesity or nutrition is funded by a food or beverage company, be skeptical of conclusions that emphasize exercise or specific nutrients while ignoring the role of highly processed foods. Prioritize research that is independent of industry funding or focuses on whole dietary patterns rather than isolated components.

Research funded by the sugar-sweetened beverage (SSB) industry is significantly more likely to reach weak or null conclusions regarding the adverse health effects of SSB consumption compared to independently funded research.

When evaluating health claims about sugary drinks, prioritize studies funded by government, universities, or independent foundations over those funded by the beverage industry. Industry-funded studies are statistically much more likely to downplay health risks, potentially delaying necessary public health interventions like taxes or labeling laws.

Bariatric surgery confers a protective effect against cancer mortality, potentially driven by weight loss and intrinsic surgical changes.

Bariatric surgery significantly reduces the risk of dying from cancer (by 60%). This benefit is a major driver of the overall mortality reduction seen in surgical patients.