Browse the evidence

Resistance exercise stimulates muscle hypertrophy primarily through the activation of the mTOR pathway via PKB, while endurance exercise stimulates mitochondrial biogenesis primarily through AMPK activation of PGC-1alpha.

Understanding that strength and endurance use different molecular switches helps explain why you cannot maximize both simultaneously. To build muscle, focus on high-intensity resistance to activate PKB/mTOR. To improve endurance, focus on duration to activate AMPK/PGC-1alpha.

Visceral obesity is strongly associated with the 'metabolic syndrome' (hypertension, hyperlipidemia, hyperinsulinemia, and insulin resistance), whereas subcutaneous fat is not.

Where you store fat matters more for your health than how much you weigh. If you have excess fat around your waist (visceral fat), you are at significantly higher risk for heart disease and diabetes compared to someone who stores fat in their hips or thighs (subcutaneous fat), even if their total weight is the same.

Increasing relative exercise intensity shifts fuel utilization from fat to carbohydrate, with carbohydrate becoming the predominant fuel source above the 'crossover point' (typically ~50% VO2max in untrained individuals).

As you exercise harder (higher % of your max capacity), your body switches from burning fat to burning sugar. For fat loss purposes, moderate intensity allows for higher fat oxidation, but high intensity burns more total calories and sugar.

Low-protein diets (10-15% energy) result in a greater reduction in hsCRP compared to high-protein diets (25-30% energy) during weight maintenance, independent of glycemic index.

To further lower inflammation after weight loss, consider not over-consumption protein. A moderate protein intake (around 10-15% of calories) may support lower inflammatory markers (hsCRP) better than a high-protein diet, although lipid and blood pressure benefits were similar across protein levels.

Sarcopenia is defined by the loss of muscle mass, strength, and physical function, and its prevalence varies significantly depending on the definition used.

Sarcopenia is a serious condition involving loss of muscle mass, strength, and function. Its diagnosis depends on the specific criteria used, so prevalence rates vary widely.

Folate deficiency causes extensive incorporation of uracil into human DNA, leading to chromosome breaks and increased colon cancer risk.

If you do not consume enough folate-rich foods (leafy greens, legumes), consider a multivitamin or folate supplement. This is especially important if you have a genetic variant (MTHFR) that affects folate processing, as this can increase your risk of DNA damage and colon cancer.

Statins reduce cardiovascular events and inflammatory markers (CRP) but may increase the risk of new-onset diabetes, indicating a trade-off between cardiovascular protection and glycemic control.

Statins are highly effective at preventing heart attacks and strokes, even in people with normal cholesterol but high inflammation. However, they can slightly increase the risk of developing diabetes. For most people with cardiovascular risk, the heart protection outweighs this risk. Monitor your blood sugar if you start statins.

Melatonin regulates circadian rhythms and sleep-wake cycles by acting on the suprachiasmatic nucleus (SCN) and pineal gland, with secretion peaking at night.

Melatonin is your body's natural signal for darkness and sleep. It is produced by the pineal gland in response to darkness, peaks at night, and helps regulate your sleep-wake cycle. Exposure to light at night suppresses this natural production.

Leptin regulates body weight by acting on hypothalamic arcuate nucleus neurons, specifically by inhibiting NPY/AGRP (anabolic) neurons and stimulating POMC/CART (catabolic) neurons.

Your body uses leptin to tell your brain how much fat you have. In obesity, this signal is often ignored (resistance). Simply having high leptin (from high body fat) doesn't fix the problem because the brain's receptors aren't responding correctly. The focus should be on improving metabolic health rather than just leptin levels.

Higher body mass index (BMI), abdominal fatness (waist circumference), and total body fat mass are associated with a significantly increased risk of developing atrial fibrillation, with risk increasing non-linearly at higher BMI levels.

Maintain a healthy body weight and minimize abdominal fat to lower your risk of atrial fibrillation. This risk increases even within the 'normal' BMI range (starting around 22) and is strongly linked to waist size and total body fat mass, not just obesity. Focus on keeping your waist circumference low and overall fat mass in check, as these are significant, modifiable risk factors for heart rhythm disorders.

Current alcohol use results in a net mortality burden, with deaths from other causes outweighing the averted deaths from ischemic heart disease, ischemic stroke, and diabetes.

Be aware that alcohol has a net negative impact on mortality. While it may offer some protection against heart disease and diabetes, the risks from cancer, liver disease, and injuries outweigh these benefits. Limiting or avoiding alcohol can improve overall health outcomes.

Tirzepatide treatment is associated with a higher incidence of gastrointestinal adverse events (nausea, diarrhea, vomiting) compared to placebo and insulin, and slightly higher than GLP-1 RAs, though serious adverse events are not significantly different from placebo.

Expect gastrointestinal side effects like nausea, diarrhea, or vomiting, especially when starting or increasing the dose. These are usually mild and go away. Serious side effects (like pancreatitis or heart issues) did not show a statistically significant increase compared to placebo in this analysis. Monitor your symptoms and report severe or persistent issues to your doctor.

Tirzepatide use is associated with a significantly higher incidence of gastrointestinal adverse events, specifically nausea, vomiting, and diarrhea, compared to placebo, although serious adverse event rates remain comparable.

Expect gastrointestinal side effects when starting tirzepatide. Nausea, vomiting, and diarrhea are significantly more common than with a placebo, particularly when starting or increasing the dose. However, these are typically mild to moderate and do not appear to increase the risk of serious health events. Most patients tolerate the medication well enough to continue treatment, which is necessary to achieve the significant weight loss benefits.

Fad diets, supplements, and unproven therapies (e.g., phytotherapics, probiotics for weight loss) are ineffective and potentially harmful for obesity treatment.

Avoid fad diets and unproven supplements (phytotherapics, probiotics, caffeine supplements) for weight loss. They are ineffective and may be harmful. Focus on evidence-based strategies like calorie restriction and behavioral changes.

Tirzepatide is associated with a higher incidence of gastrointestinal adverse events (nausea, vomiting, constipation, dyspepsia) compared to placebo, which increases with dose and leads to higher discontinuation rates, but does not increase the risk of serious adverse events.

Tirzepatide is more likely to cause stomach issues like nausea and vomiting than a placebo, and these side effects are more common at higher doses. This can lead to some people stopping the medication, but it does not increase the risk of serious health problems. Managing these side effects is key to staying on the treatment.

Tirzepatide use is associated with a significantly higher incidence of adverse reactions, particularly nausea and diarrhea, which are dose-dependent and increase with higher doses (15mg).

Be prepared for potential side effects like nausea and diarrhea when starting Tirzepatide. These side effects are more likely at higher doses (15mg) and may decrease over time as your body adjusts. Most people tolerate the medication well, but it's important to discuss these potential side effects with your doctor.

Tirzepatide use is associated with a significantly increased incidence of adverse reactions, particularly gastrointestinal issues like nausea and diarrhea, which are dose-dependent.

Be prepared for potential side effects when starting Tirzepatide. Nausea and diarrhea are common, especially when you first start or increase the dose. These symptoms often improve over time. Starting at a lower dose (2.5mg) and gradually increasing can help your body adjust. Most people find the side effects manageable.

Obesity is a complex chronic disease driven by biological, behavioral, and environmental factors, not merely a result of personal irresponsibility or lack of willpower.

Stop blaming yourself or others for obesity. It is a chronic disease with biological roots, not a moral failing. Seek healthcare providers who treat it as such, focusing on health outcomes rather than just weight loss.

Obesity is a causal factor for many types of cancer, including colorectal, endometrial, kidney, and postmenopausal breast cancer.

Maintaining a healthy weight reduces your risk of developing several common cancers, including colorectal, kidney, and postmenopausal breast cancer.

Fat-free mass-adjusted total and basal energy expenditure peaks at approximately 50% above adult levels around 1 year of age, then declines to adult baseline levels by age 20, remaining stable through age 60 before declining in older adults.

Your body's energy needs change predictably as you age. You burn significantly more energy relative to your size as a toddler (peaking around age 1) than as an adult. As you age from 20 to 60, your metabolic rate (adjusted for size) stabilizes. After 60, it declines. Do not assume your metabolic rate is constant or scales linearly with your weight; use age- and size-specific estimates for nutritional planning rather than simple weight-based ratios.

Replacing carbohydrates with Saturated Fat (SFA) has no significant effect on fasting glucose, though it may slightly lower fasting insulin.

If you swap carbohydrates for saturated fats, do not expect your fasting blood glucose to improve. While it may slightly lower fasting insulin, it does not offer the broader metabolic benefits (like improved HbA1c and insulin secretion) that replacing carbs with polyunsaturated fats does.

Supplementation with glutamine or arginine does not enhance muscle protein synthesis or hypertrophy in healthy, well-nourished individuals performing resistance or endurance exercise.

Do not waste money on glutamine or arginine supplements for muscle building. They have been shown to have no effect on muscle protein synthesis or strength gains in healthy people.

Different methods of measuring muscle hypertrophy (e.g., ultrasound, DXA, MRI, biopsy) often yield poorly correlated results, making it difficult to determine if true hypertrophy has occurred using a single metric.

Do not rely on a single measurement tool to judge your progress. Ultrasound, DXA, and MRI measure different things (thickness, lean mass, volume) and may not correlate with each other or with actual strength gains. If you are tracking progress, use multiple metrics (strength, visual, maybe one imaging modality) and understand that 'size' is a complex, multi-component adaptation.

High-fat, low-carbohydrate diets impair high-intensity endurance performance by down-regulating pyruvate dehydrogenase (PDH) activity and reducing muscle glycogenolysis rates, thereby limiting ATP production at intensities above 60% VO2max.

If you train or race at high intensities (above 60% of your max effort), avoid high-fat, low-carb diets. They slow down your body's ability to use carbohydrates, which are your primary fuel for speed. Stick to high-carbohydrate availability to maintain performance.