Browse the evidence

Functional Overreaching (FOR) is a normal part of training that leads to performance improvement after recovery, whereas Non-Functional Overreaching (NFOR) and Overtraining Syndrome (OTS) involve prolonged maladaptation and performance decrements that take weeks or months to resolve.

Expect temporary performance dips during intense training blocks. This is 'Functional Overreaching' and is necessary for improvement. If the dip lasts weeks or months and is accompanied by mood disturbances or hormonal changes, it may be 'Non-Functional Overreaching' or 'Overtraining Syndrome,' requiring extended rest and medical evaluation.

The association between BMI and diabetes prevalence is strongest in South Asian countries (India, Bangladesh) and weakest in Japan, suggesting geographic and ethnic variations in diabetes risk at a given BMI.

Diabetes risk at a given body weight varies by where you are from. This study found that for South Asians (Indian, Bangladeshi), the link between high BMI and diabetes is stronger than for East Asians (Japanese). This suggests that South Asian individuals might benefit from maintaining a lower BMI target to prevent diabetes compared to other Asian ethnicities.

Racial and ethnic minority groups in the US experience significantly worse sleep health outcomes, including shorter duration, lower efficiency, and higher prevalence of sleep disorders, compared to non-Hispanic Whites.

If you belong to a racial or ethnic minority group, you may face systemic barriers that make getting adequate sleep harder, regardless of your personal habits. Focus on controllable factors like sleep hygiene and stress management, but recognize that advocating for policy changes and community support is also part of addressing sleep health disparities.

Dietary intake of L-carnitine is primarily derived from red meat, with vegetarians likely to have lower levels due to the absence of carnitine in plant-based foods.

To get L-carnitine, eat red meat like lamb or beef. If you are a strict vegetarian, you likely get very little carnitine from your diet.

Sleep is essential for vital physiological functions including development, energy conservation, brain waste clearance, immune modulation, cognition, and performance, with no single unified role but rather multiple necessary processes.

Prioritize sleep duration and quality as non-negotiable for health, not just rest. It actively clears brain waste, consolidates memory, and regulates immunity. Sacrificing sleep for productivity undermines the cognitive and physical benefits you seek.

Obesity causes restrictive lung disease patterns (reduced ERV, FRC, TLC) primarily through mechanical restriction from adipose tissue deposition on the chest and abdomen, rather than intrinsic airway obstruction.

Your breathing difficulties are likely due to the physical weight of fat on your chest and abdomen restricting your lungs, not necessarily a disease like asthma. This 'restrictive' pattern means your lungs can't expand fully. Losing weight reduces this physical burden, allowing your lungs to expand more easily and improving your capacity. This is distinct from obstructive diseases where airways are narrowed.

Metabolic dysfunction (Metabolic Syndrome) significantly increases CHD risk regardless of body weight, with metabolically unhealthy normal weight individuals having more than double the risk of metabolically healthy normal weight individuals.

If you are normal weight, you are not immune to heart disease. If you have high blood pressure, high triglycerides, low HDL, high blood sugar, or a large waist, your risk is more than double that of a normal weight person with healthy metabolic markers. Address these metabolic issues through lifestyle changes or medication.

Day-to-day variation in food intake means that short-term measurements (e.g., 24 hours) are unlikely to reflect habitual intake, requiring statistical adjustment or multiple days of data for accurate assessment.

If you want to know your habitual diet, track for multiple days or use statistical methods to adjust for day-to-day variation. A single day's record is not enough to represent your long-term habits.

In East Asians, a body mass index (BMI) of 25.0 or higher is associated with a significantly increased risk of cardiovascular disease mortality, with the lowest risk observed in the BMI range of 20.0-22.4.

If you are East Asian, maintaining a BMI between 20.0 and 22.4 is associated with the lowest risk of cardiovascular death. A BMI of 25 or higher is linked to increased risk, suggesting that standard Western 'overweight' thresholds may be too high for this demographic. Focus on maintaining a healthy weight through balanced nutrition and physical activity, rather than aiming for the lowest possible BMI, as very low BMI (<17.5) is also associated with higher CVD risk.

Critical Power (CP) is the gold standard for defining the maximal metabolic steady state, whereas Maximal Lactate Steady State (MLSS) systematically underestimates this threshold due to methodological limitations.

Stop using Maximal Lactate Steady State (MLSS) or arbitrary 60-minute functional thresholds as your primary guide for endurance capacity. Instead, determine your Critical Power (CP) using a power-duration curve model. CP accurately separates the 'heavy' intensity domain (where homeostasis is possible) from the 'severe' domain (where fatigue is inevitable). Training prescriptions based on CP are more physiologically robust than those based on MLSS, which tends to underestimate your true sustainable power.

Second-generation antipsychotics, particularly clozapine and olanzapine, cause significant weight gain in patients with schizophrenia, driven by increased caloric intake (orexigenic effects) and potentially altered energy expenditure.

If you are taking clozapine or olanzapine for schizophrenia, expect significant weight gain due to biological changes in hunger and food preference, not just lifestyle. This is a known side effect of the medication, not a personal failure. Proactive management with behavioral interventions and potentially switching to lower-risk medications (if clinically appropriate) is necessary.

Metformin is the most effective pharmacological adjunct for treating antipsychotic-induced weight gain, resulting in significant weight loss compared to placebo.

If you are gaining weight on antipsychotics, ask your doctor about metformin. It is the most proven medication to help counteract this specific type of weight gain and has a good safety profile. It works best when combined with lifestyle changes.

HMB supplementation is safe in humans, with no adverse effects on blood chemistry, hematology, or organ function at doses up to 3-4 g/day.

HMB is safe for human consumption at doses used for muscle building (up to 4g/day), with no negative impacts on liver, kidney, or blood markers.

Standardized exercise training produces highly variable cardiorespiratory fitness (CRF) responses in humans, with a significant portion of individuals showing no improvement (non-responders) despite adherence to prescribed protocols.

If you exercise consistently but see no change in your fitness tests, you are likely a 'non-responder' to that specific dose. This is common and often genetic. Do not stop exercising, as other health benefits likely persist. Consider adjusting the type, intensity, or duration of exercise to find a protocol that works for your biology.

Reduced HRV is a consistent predictor of various diseases, including diabetes, cardiovascular disease, obesity, and psychiatric disorders, and is associated with inflammation and insulin resistance.

Monitor your HRV as a general indicator of your health status. Consistently low HRV may be a sign of underlying issues such as inflammation, insulin resistance, or stress. While not a diagnostic tool on its own, it can help identify individuals at risk for cardiovascular, metabolic, and psychiatric conditions, prompting earlier lifestyle interventions or medical consultation.

Fermentation of dietary fibers by gut bacteria produces short-chain fatty acids (SCFAs) like butyrate, acetate, and propionate, which reduce inflammation, provide energy to colon cells, and regulate metabolism.

Eat fiber-rich foods to feed your gut bacteria, which will produce beneficial short-chain fatty acids that reduce gut inflammation and support colon health.

Bariatric surgery reduces overall mortality by 25–50% in the long term and is the most effective treatment for morbid obesity.

If you have severe obesity (BMI >40, or >35 with health issues), bariatric surgery is the most effective medical intervention available. It doesn't just help you lose weight; it significantly reduces your risk of dying from obesity-related causes like heart disease and diabetes. Consult a specialist to see if you qualify.

Higher muscle strength (specifically grip and knee extension) in young adulthood is independently associated with a lower incidence of coronary heart disease and stroke later in life, even after adjusting for body mass index, blood pressure, and socioeconomic status.

Prioritize building functional muscle strength, particularly grip and leg strength, as a long-term strategy for heart health. This benefit is independent of your body weight. Incorporate resistance training into your routine to reduce your risk of coronary heart disease and stroke later in life.

Being underweight in young adulthood is associated with an increased risk of intracerebral and subarachoid hemorrhage (stroke types), whereas obesity is associated with increased risk of coronary heart disease and intracerebral infarction.

Maintain a healthy body weight range. While obesity is a known risk for heart disease and ischemic stroke, being underweight in young adulthood is also a risk factor for hemorrhagic stroke. Aim for a balanced weight rather than extreme leanness.

Secular trends in the UK indicate that younger birth cohorts (born after the 1980s) develop overweight or obesity at significantly younger ages and with higher probabilities than older cohorts (born before the 1980s).

If you are raising children in a modern high-income environment, expect a higher baseline risk of overweight/obesity compared to previous generations. The data suggests this risk manifests earlier (childhood/adolescence) rather than just in adulthood. Focus on early-life environmental factors (diet, activity) as the primary lever for prevention, as the 'normal' trajectory has shifted.

Maximal oxygen uptake (VO2max) and maximal heart rate decline with age at rates of approximately 3.5 mL/kg/min and 6 beats/min per decade, respectively, starting from peak values in the 20-29 age group.

Your fitness naturally declines as you age, but you can slow this down. Focus on maintaining physical activity, especially if you are a woman over 50, as activity levels have a stronger impact on your VO2max than on men in the same age bracket. Don't rely on the '220 minus age' rule for heart rate; it overestimates the decline.

Moderate or non-excessive alcohol consumption, along with above-median fruit and vegetable intake, are key components driving the mortality-reducing association of the Mediterranean Diet.

To maximize longevity benefits, prioritize high intake of fruits and vegetables, include moderate alcohol if you already drink, and limit meat intake, as higher meat consumption was associated with increased mortality risk in this analysis.

High body mass index (BMI > 25 kg/m²) is a major global health risk factor that has caused a more than 2.5-fold increase in global deaths and disability-adjusted life years (DALYs) between 1990 and 2021, with cardiovascular diseases and diabetes being the leading causes of this burden.

High body mass index (BMI) is a major, modifiable risk factor for serious diseases like heart disease, diabetes, and kidney disease. The global burden of disease from high BMI has more than doubled in 30 years. To protect your health, it is crucial to monitor your BMI and work towards maintaining a healthy weight through sustainable lifestyle changes, as high BMI significantly increases your risk of premature death and disability.

Obesity is primarily driven by excessive energy intake and physical inactivity, mediated by impaired central brain circuit regulation and neuroendocrine hormone dysfunction.

Focus on sustainable changes to energy intake and physical activity, but recognize that biological factors like hormones and brain circuits play a major role. If lifestyle changes are insufficient, consult a healthcare provider about medical interventions like drugs or surgery.