Browse the evidence

Tournament wrestling involving 6% body weight loss followed by multiple matches over two days causes progressive, significant reductions in lower body power and upper body isometric strength, alongside elevated physiological stress markers (testosterone, cortisol, lactate, norepinephrine, epinephrine, and plasma osmolality).

If you are a wrestler, be aware that losing 6% of your body weight and then competing in multiple matches over two days will significantly reduce your strength and power. Your body will also experience high levels of stress, indicated by changes in hormones and metabolic markers. To maintain performance, consider strategies that minimize extreme weight loss and prioritize recovery between matches.

Dietary intake of nondigestible carbohydrates (resistant starch, prebiotics) directly influences the species composition and total numbers of the human colonic microbiota.

To change your gut bacteria, you must eat nondigestible carbohydrates like resistant starch and prebiotics. These feed specific bacteria that produce beneficial metabolites. If you don't see changes, you might lack the specific bacteria needed to process these foods, but the potential for change exists.

Increased dietary fiber intake lowers colonic pH, which selectively suppresses Bacteroides spp. and promotes butyrate-producing gram-positive bacteria.

Eating more fiber not only feeds good bacteria directly but also creates an acidic environment in the gut that favors beneficial bacteria and suppresses others.

Exercise-induced production of reactive species (ROS) acts as a necessary signaling mechanism that triggers beneficial physiological adaptations, including angiogenesis, mitochondrial biogenesis, and muscle hypertrophy, rather than solely causing damage.

Do not fear the 'burn' or oxidative stress from exercise; it is the signal your body needs to build better blood vessels, more energy-producing mitochondria, and stronger muscles. You do not need to neutralize this stress with high-dose antioxidants, as doing so might prevent these adaptations.

Large-scale food fortification (LSFF) of staple foods (flour, salt, oil, sugar) significantly reduces the prevalence of anemia, goiter, and neural tube defects in low- and middle-income countries.

In regions where staple foods like flour, salt, or oil are not fortified, seek out fortified versions or ensure diverse intake of nutrient-dense whole foods. For populations relying on staples, mandatory fortification is the most effective public health tool to prevent anemia and birth defects.

Exercise promotes glucose uptake in skeletal muscle via an insulin-independent mechanism involving AMPK activation, distinct from the insulin signaling pathway.

Exercise helps your muscles take up glucose directly, even if your insulin sensitivity is low. This happens through the activation of AMPK, a cellular energy sensor. This is why physical activity is beneficial for blood sugar control regardless of insulin resistance status.

Pre-rolling with foam rollers provides a small but statistically significant improvement in sprint performance (+0.7%) and flexibility (+4.0%), while having negligible effects on jump and strength performance.

Use foam rolling as a warm-up before sprinting or activities requiring high flexibility. Expect small gains in speed (approx 0.7%) and range of motion (approx 4%). Do not expect it to boost your max lift or vertical jump. If you are a recreational athlete, these small gains might be negligible; if you are elite, they may be worthwhile.

Post-rolling (post-exercise foam rolling) slightly attenuates exercise-induced decreases in sprint and strength performance and reduces perceived muscle pain, but has trivial effects on jump performance recovery.

Use foam rolling after workouts to help manage muscle soreness and slightly preserve your sprint and strength capabilities for subsequent sessions. Do not expect it to restore your vertical jump or max strength quickly. It is a useful tool for comfort and minor performance preservation, not a magic recovery bullet.

Pre-pregnancy underweight (BMI <18.5) significantly increases the risk of preterm birth by 32% and small-for-gestational age babies by 64%.

If you are underweight before pregnancy, you are at higher risk for having a preterm or small baby. Focus on achieving a healthy weight through balanced nutrition before conceiving to reduce these risks.

Pre-pregnancy overweight and obesity significantly increase the risk of preeclampsia, gestational diabetes, and cesarean delivery.

If you are overweight or obese before pregnancy, you are at higher risk for high blood pressure disorders, gestational diabetes, and needing a C-section. Working towards a healthier weight before conceiving can significantly lower these risks.

Elevated serum androstenedione (A) is a stronger predictor of insulin resistance and metabolic dysfunction in women with Polycystic Ovary Syndrome (PCOS) than serum testosterone (T), with high A levels correlating to lower insulin sensitivity regardless of T status.

For women with PCOS, relying solely on testosterone levels may miss those at highest risk for insulin resistance and metabolic issues. Measuring androstenedione alongside testosterone provides a more complete picture of androgen excess and better predicts metabolic health risks.

PCOS patients with high androstenedione and normal testosterone (HA/NT) exhibit significantly higher insulin resistance and dysglycemia rates compared to those with normal levels of both androgens (NA/NT), despite having normal testosterone.

If you have PCOS and your testosterone is normal, you are not automatically clear of metabolic risk. If your androstenedione is high, you may still have insulin resistance and a higher risk of developing diabetes, so monitoring glucose metabolism is important.

Weight loss via a low-calorie, low-fat diet significantly increases Sex Hormone-Binding Globulin (SHBG) and decreases Androstenedione levels in obese, hirsute women, regardless of metformin use.

Lose weight by eating fewer calories (around 1500) and reducing fat intake to 30% of your diet. This will naturally raise your SHBG and lower androgens, improving hirsutism markers over 4 months.

Low energy availability (EA < 45 kcal/kg FFM/day) in female endurance athletes causes a significant reduction in resting metabolic rate (RMR), serving as an energy-preserving mechanism.

If you are a female endurance athlete, maintaining a normal BMI does not guarantee you are eating enough to support your training. If you train heavily, you must ensure your energy availability is at least 45 kcal/kg of fat-free mass per day to prevent your metabolism from slowing down and to protect your menstrual and bone health. Monitor your energy intake relative to your training load, not just your scale weight.

Menstrual dysfunction (MD) in female endurance athletes is associated with lower resting metabolic rate (RMR) compared to eumenorrheic athletes, independent of energy availability status.

If you are a female endurance athlete and your menstrual cycle has become irregular or stopped, do not assume it is normal. This is a sign that your body is under stress, possibly from low energy intake, and your metabolism may be slowing down. Seek medical evaluation to assess your energy availability and hormonal health.

The modest weight loss observed from aerobic exercise interventions is primarily caused by low prescribed exercise energy doses combined with a compensatory increase in caloric intake, rather than metabolic adaptation or reduced non-exercise activity.

If you are exercising to lose weight but not seeing results, do not assume your metabolism has slowed down. The most likely culprits are that your exercise dose is too low to create a significant deficit, or you are unconsciously eating more to compensate for the activity. To lose weight, you must either increase the intensity/duration of exercise significantly or, more effectively, manage your caloric intake to ensure it does not rise to match your increased expenditure.

Deliberate overreaching via progressive overload training in team sport athletes causes significant reductions in muscular strength, power, and endurance, primarily driven by increased muscle damage and a shift toward a catabolic state.

If you are feeling consistently fatigued and your performance is dropping despite hard training, you may be overreached. The solution is not to train harder, but to reduce your training volume and intensity for about a week (tapering). This allows your body to recover from muscle damage and hormonal imbalances, often resulting in improved strength, power, and endurance once you return to normal training.

A decreased testosterone-to-cortisol (T/C) ratio and elevated creatine kinase (CK) activity are biochemical markers indicating a catabolic state and muscle damage associated with overreaching.

Monitoring hormonal balance can help identify when you are overtrained. A drop in the testosterone-to-cortisol ratio and high creatine kinase levels indicate your body is in a catabolic (breaking down) state. If you have access to blood testing, these markers can guide your recovery needs. If not, focus on subjective feelings of fatigue and performance drops as proxies.

Erectile dysfunction in diabetic men is strongly associated with cardiovascular disease, often preceding coronary artery disease by 2-5 years, making ED a predictor of cardiac risk.

Erectile dysfunction is not just a sexual problem; it is a warning light for your heart. In diabetic men, ED often appears 2-5 years before heart disease symptoms. If you experience ED, request a cardiovascular risk assessment, as treating the underlying vascular issues can prevent future cardiac events.

Higher plasma adiponectin levels are positively associated with greater insulin-stimulated glucose utilization (M) in adult women, independent of age, while adiponectin levels are negatively associated with visceral and subcutaneous abdominal fat.

For adult women, maintaining lower abdominal fat (visceral and subcutaneous) is associated with higher levels of adiponectin, a hormone that improves how your body uses glucose. While age itself does not lower adiponectin, the accumulation of abdominal fat often does. Focusing on reducing abdominal fat and improving insulin sensitivity may support healthier adiponectin levels.

An 8% tax on nonessential energy-dense foods and a peso-per-liter tax on sugar-sweetened beverages in Mexico resulted in a statistically significant decline in the volume of purchased taxed foods compared to pre-tax trends, with the largest reductions observed in low socioeconomic status (SES) households.

If you are a policymaker or public health advocate, this evidence supports the implementation of taxes on energy-dense, non-essential foods and sugar-sweetened beverages. The intervention is effective at reducing purchase volumes, particularly among lower-income populations who benefit most from the reduction. However, the tax definition must be carefully crafted to avoid loopholes like product reformulation to fall under the threshold.

A low-fat dietary intervention (reducing fat intake to 15% of calories) improves recurrence-free survival and overall survival in breast cancer survivors, particularly those with hormone-receptor-negative disease or without hot flushes.

For breast cancer survivors, reducing dietary fat to around 15% of total calories may improve survival outcomes, especially if you do not have hot flushes. This should be done through structured counseling and regular monitoring, not just self-guided changes. Focus on reducing fat intake specifically, as simply eating more fruits and vegetables without reducing fat did not show the same benefits.

Six months of resistance training improves absolute glucose disposal in nonobese young women primarily through increased fat-free mass (mass effect) without altering intrinsic muscle insulin sensitivity.

If you are a young, healthy woman, doing resistance training three times a week for six months will improve your body's ability to manage blood sugar. This happens because you are building more muscle mass, which acts as a larger sink for glucose, rather than by losing fat. You do not need to lose weight to see this metabolic benefit.

Six months of endurance training improves intrinsic muscle insulin sensitivity (glucose disposal per unit of fat-free mass) in nonobese young women, independent of changes in body composition or aerobic capacity.

If you are a young, healthy woman, doing endurance exercise three times a week for six months will improve your muscles' ability to use glucose. This happens because the exercise changes how the muscle itself processes sugar, not because you lost weight or got fitter in terms of VO2 max. You do not need to lose fat to get this specific metabolic benefit.