Browse the evidence

Female reproductive ability, including the onset of menarche and the maintenance of regular ovulatory cycles, is dependent on maintaining a critical minimum body weight and a specific body fat percentage (approximately 17% at menarche and 22-28% in adulthood), rather than chronological age alone.

For women, achieving and maintaining a minimum body weight and body fat percentage (roughly 17-22% depending on life stage) is biologically required for regular ovulation and fertility. Significant weight loss (10-15% of body weight) or excessive exercise can halt menstrual cycles, regardless of chronological age. Restoring cycles requires reaching a specific weight-for-height threshold, not just feeling 'healthy'.

Low Glycemic Index (GI) and Low Glycemic Load (GL) diets are associated with higher HDL-cholesterol, reduced triglycerides, and lower incidence of diabetes and cardiovascular disease.

Focus on the quality of your carbohydrates rather than just cutting them out. Choose low Glycemic Index foods like whole grains, legumes, and vegetables. This approach helps maintain higher HDL ('good') cholesterol, lowers triglycerides, and reduces the risk of diabetes and heart disease compared to high GI foods.

Testosterone supplementation in older men induces skeletal muscle hypertrophy and increases satellite cell number through the activation of the Notch signaling pathway and increased satellite cell replication.

For older men experiencing muscle loss, testosterone therapy (when medically indicated and monitored) can effectively rebuild muscle mass by activating satellite cells. This process relies on the body's natural repair mechanisms, which remain functional in older age, contrary to the belief that aging permanently disables muscle growth potential. Treatment requires medical supervision due to potential side effects.

In women, visceral adipose tissue (VAT) is significantly more strongly associated with insulin resistance and impaired insulin secretion than abdominal subcutaneous adipose tissue (SAT), whereas in men, both fat depots are associated with insulin resistance to a similar extent.

If you are a woman, carrying fat around your organs (visceral fat) is much more dangerous for your insulin sensitivity than carrying fat under your skin (subcutaneous fat). Men are less discriminating; both types of abdominal fat affect their insulin resistance similarly. Because waist size alone doesn't tell you where the fat is located, relying solely on it may underestimate metabolic risk in women. Focus on reducing overall adiposity, as visceral fat is the primary driver of insulin resistance in women.

Gender-affirming hormone therapy significantly reduces mental health morbidity, including depression and anxiety, in transgender individuals.

If you are transgender and experiencing significant distress related to your gender identity, accessing gender-affirming hormone therapy under medical supervision is strongly associated with significant improvements in mental health, including reduced depression and anxiety. While physical risks exist, they should be managed through careful monitoring and appropriate medication selection (e.g., transdermal estrogen for those at high thrombotic risk), as the mental health benefits are substantial.

Insomnia disorder is an independent risk factor for the development of mental health disorders, including depression, anxiety, and suicide, suggesting that treating insomnia may have preventive value for these conditions.

Treat insomnia seriously not just for sleep quality, but as a critical step in preventing depression and anxiety. Addressing sleep problems early may reduce the risk of developing these mental health conditions.

Short-term vitamin D3 supplementation (120,000 IU every two weeks for 6 weeks) improves postprandial insulin sensitivity (measured by OGIS) in centrally obese, non-diabetic men, but does not affect fasting insulin sensitivity, lipid profiles, or blood pressure.

If you are a centrally obese man over 35 with low vitamin D, taking 120,000 IU of Vitamin D3 every two weeks for six weeks may help your body handle sugar after meals better. However, do not expect this to lower your fasting blood sugar, improve your cholesterol, or lower your blood pressure. It is a targeted intervention for postprandial sensitivity, not a general metabolic fix.

Cotadutide, a dual GLP-1 and glucagon receptor agonist, significantly improves hepatic parameters (AST, ALT, FIB-4, NFS, PRO-C3) and lipid profiles (triglycerides) in patients with type 2 diabetes and obesity, with effects on liver enzymes appearing independent of weight loss.

For individuals with type 2 diabetes and obesity, cotadutide (a dual GLP-1/glucagon agonist) offers significant improvements in liver health markers (like AST, ALT, and fibrosis scores) and triglyceride levels, potentially beyond what standard GLP-1 drugs like liraglutide achieve. This benefit appears linked to the glucagon component of the drug. Treatment involves daily subcutaneous injections, starting at a low dose and titrating up, which helps manage initial gastrointestinal side effects like nausea. Patients should discuss this option with their healthcare provider, especially if they have concerns about liver health or lipid profiles.

Shifting dietary fat quality from saturated to polyunsaturated (increasing the P/S ratio) consistently lowers plasma cholesterol levels, whereas increasing dietary cholesterol quantity has a marginal effect on plasma cholesterol in the majority of individuals.

Focus on the type of fat you eat rather than strictly avoiding dietary cholesterol. Replacing saturated fats (like those in dairy or fatty meats) with polyunsaturated fats (like vegetable oils) is a more reliable way to lower plasma cholesterol than simply cutting back on eggs or shrimp. Most people's bodies naturally adjust to higher cholesterol intake, but they respond consistently to changes in fat quality.

Chronic antioxidant supplementation (specifically Vitamin C and E) interferes with skeletal muscle adaptation to exercise training by attenuating improvements in insulin sensitivity, mitochondrial biogenesis, and antioxidant capacity.

If you are training regularly, avoid taking high-dose Vitamin C and E supplements. They block the molecular signals your body needs to build mitochondria and improve insulin sensitivity. Let the exercise stress do its job.

Antioxidant supplementation consistently blunts skeletal muscle hypertrophy and strength gains following resistance or high-intensity training, unlike endurance training where performance may be unaffected.

If you lift weights or do high-intensity intervals, do not take Vitamin C or E supplements. They block the signals your muscles need to grow stronger and larger. Focus on the training itself.

Sleep restriction (4-5 hours/night) impairs glucose metabolism and insulin sensitivity to levels similar to those seen in pre-diabetic or diabetic populations.

Chronic sleep restriction (4-5 hours/night) can impair your body's ability to regulate blood sugar to levels seen in pre-diabetic individuals. This happens even if you maintain a healthy weight. Prioritize 7-9 hours of sleep to protect your long-term metabolic health and reduce your risk of type 2 diabetes.

Sleep-disordered breathing (SDB) causes impairments in insulin sensitivity, glucose effectiveness, and pancreatic beta-cell function independent of adiposity, thereby increasing the risk of type 2 diabetes.

If you have symptoms of sleep apnea (snoring, daytime fatigue), get tested. Treating sleep-disordered breathing is crucial for metabolic health and diabetes prevention, regardless of your weight. The metabolic damage from poor sleep is distinct from the damage caused by excess body fat.

Psychological stress activates the hypothalamic-pituitary-adrenal (HPA) axis and sympathetic nervous system, leading to hyperarousal, elevated cortisol, and sleep-onset insomnia.

If you are stressed, your body is physically in 'wake mode' due to hormones like cortisol. You cannot simply 'relax' your way to sleep if the physiological stress response is active. Managing stress requires addressing the physiological arousal, not just the thoughts.

Chronic stress and insomnia create a vicious cycle where sleep loss further activates the HPA axis and immune system, exacerbating stress sensitivity.

Chronic insomnia is not just a symptom of stress; it is a cause of further stress. To break the cycle, you must address the physiological hyperarousal (high cortisol, high heart rate) that persists even when you are not consciously stressed.

Cytokines (IL-1beta, TNF) regulate sleep homeostasis, and stress-induced immune activation can disrupt sleep by altering cytokine levels.

Your immune system plays a direct role in how well you sleep. Inflammation or immune activation (from stress or illness) can disrupt sleep through cytokines like IL-1beta and TNF.

Low serum testosterone levels (defined as <8.7 nmol/L or <250 ng/dL) are associated with a significantly increased risk of all-cause, cardiovascular, and cancer mortality in men aged 20-79, independent of age, waist circumference, smoking, alcohol use, physical activity, and renal function.

For men aged 20-79, having serum testosterone below 8.7 nmol/L (250 ng/dL) is a significant predictor of higher all-cause, cardiovascular, and cancer mortality risk, independent of lifestyle factors like smoking or exercise. This association holds even after adjusting for age, waist circumference, and kidney function. While testosterone itself may not be the direct cause of death, it serves as a critical biomarker for underlying health risks, particularly in older men (60-79 years).

Higher Chinese visceral adiposity index (CVAI) is significantly associated with increased prevalence of cardiovascular disease (CVD) and diabetic kidney disease (DKD) in diabetic adults, independent of BMI.

For diabetic patients, tracking visceral fat risk via the Chinese Visceral Adiposity Index (CVAI) provides a more accurate prediction of heart and kidney disease risk than BMI alone. Clinicians should prioritize CVAI calculations to identify high-risk individuals for early intervention, particularly women who show a stronger association between CVAI and kidney disease.

Walnuts, due to their high alpha-linolenic acid (ALA) content, provide anti-arrhythmic protection against sudden cardiac death and coronary heart disease.

Include walnuts in your diet to increase alpha-linolenic acid (ALA) intake. This plant-based n-3 fatty acid helps protect against sudden cardiac death and coronary heart disease through anti-arrhythmic effects, offering a benefit comparable to marine n-3s.

Chronic sleep restriction (4-5 hours/night) and total sleep deprivation cause insulin resistance and impaired glucose tolerance in healthy adults, mimicking Type 2 Diabetes pathophysiology.

Prioritize 7-8 hours of sleep nightly. Chronic restriction to 4-5 hours impairs insulin sensitivity and glucose tolerance, increasing Type 2 Diabetes risk. This is not just about feeling tired; it is a direct metabolic stressor.

Circadian misalignment from shift work or forced desynchronization causes insulin resistance and impaired glucose tolerance, independent of total sleep time.

If you work shifts, try to eat during your 'day' (even if it's night) and sleep during your 'night' (even if it's day). Aligning food intake with your internal clock reduces insulin resistance.

A single dose of inorganic nitrate (12.9 mmol) improves exercise capacity in patients with heart failure with preserved ejection fraction (HFpEF) by increasing peak oxygen uptake and cardiac output, without improving exercise efficiency.

If you have heart failure with preserved ejection fraction, taking a specific dose of inorganic nitrate (found in beetroot juice) before exercise can help you breathe better and move more oxygen to your muscles during intense activity. However, it does not make your body more efficient at using that oxygen, and you must avoid antibacterial mouthwash to ensure the supplement works.

Type 2 diabetes acts as a coronary heart disease (CHD) equivalent, conferring a risk of myocardial infarction in diabetic patients without prior history that is equal to or greater than that of nondiabetic patients with prior myocardial infarction.

If you have Type 2 Diabetes, your risk of a heart attack is considered as high as someone who has already had one, even if you feel fine. This means you must aggressively manage blood pressure, cholesterol, and insulin resistance, not just blood sugar, to protect your heart.

Insulin resistance is a primary driver of cardiovascular disease in Type 2 Diabetes, often outweighing the direct impact of hyperglycemia on coronary heart disease risk.

For Type 2 Diabetes, managing insulin resistance (through lifestyle, weight management, and specific medications) is likely more critical for preventing heart attacks than focusing solely on lowering blood sugar levels.