Browse the evidence

Moderate dietary fructose consumption (≤50g/day or ~10% of energy) does not have deleterious effects on lipid and glucose control, and consumption up to 100g/day does not influence body weight.

You do not need to fear moderate amounts of fructose (up to 50g/day, or about 10% of your calories). It does not inherently cause weight gain or metabolic issues at this level. The problem arises from excessive consumption and overall caloric surplus, not the fructose itself. Focus on total energy balance rather than demonizing specific sugars.

High doses of fructose (unrealistic for human nutrition) can induce lipogenesis and metabolic syndrome in rodents, but these effects do not extrapolate to moderate human consumption.

Do not rely on high-dose animal studies to judge the safety of your diet. Those studies use doses of fructose that are impossible to consume in a normal human diet. At normal consumption levels, your body handles fructose differently than the stressed animal models.

Supplementation with high-dose Vitamin E and/or Vitamin C blunts skeletal muscle adaptations to endurance and resistance training, including mitochondrial biogenesis and hypertrophy signaling pathways, without improving performance metrics like VO2max.

If you are training to improve fitness or build muscle, avoid high-dose Vitamin C and E supplements. They block the cellular signals your body needs to adapt to exercise. Instead, get your antioxidants from whole foods like fruits and vegetables, which support health without interfering with your training progress.

The ventromedial prefrontal cortex (vmPFC) is specifically engaged by the goal-directed system during instrumental learning and decision-making, distinguishing it from the habitual system which relies on stimulus-response associations.

To maintain flexible, goal-oriented behavior (rather than rigid habits), you must actively engage your prefrontal cortex by evaluating the current value of outcomes. This involves consciously linking cues to specific goals and responses, rather than just reacting to stimuli automatically. This cognitive load is necessary for adapting to changing rewards.

Strength training does not significantly affect maximal oxygen uptake (VO2max), velocity at VO2max, blood lactate levels, or body composition in middle- and long-distance runners.

Do not expect strength training to increase your VO2max or change your body weight significantly. Its primary benefit lies in improving running economy and sprint speed, not aerobic capacity or body composition.

Increased appetite during a depressive episode is the primary driver of associations between depression and metabolic/inflammatory markers (BMI, metabolic syndrome components, waist circumference, CRP, TNF-α).

If you are depressed and experiencing increased appetite, this is a specific biological subtype ('immuno-metabolic depression') linked to higher inflammation and metabolic risk. It is not just 'overeating' but a symptom. Standard antidepressants may not address this. Discuss with your doctor whether treatments targeting inflammation (like anti-inflammatories or statins, though evidence is mixed) or lifestyle interventions (diet, weight loss) might be beneficial for this specific subtype.

Decreased mitochondrial biogenesis and dysregulated lipid oxidation lead to compromised skeletal muscle bioenergetic status (low ATP) and muscle wasting in early critical illness.

Early muscle loss in the ICU is driven by a failure of the muscle's energy factories (mitochondria) to produce ATP, not just by lack of movement. This metabolic shutdown prevents recovery even if nutrition is provided.

Glucagon receptor signaling regulates hepatic lipid metabolism by stimulating beta-oxidation and inhibiting lipogenesis, thereby reducing hepatic lipid accumulation.

Glucagon plays a crucial role in how your liver handles fat. While high glucagon in diabetes can be problematic, activating glucagon receptors (especially when combined with GLP-1) helps the liver burn fat and reduces liver fat storage. This is why combination therapies are effective for metabolic health.

Glucagon stimulates lipolysis in rodent adipocytes but has no significant lipolytic effect on human adipocytes at physiological concentrations.

Unlike in mice, glucagon does not directly trigger significant fat breakdown in human fat cells at normal levels. Its main job in lipid metabolism is managing fat in the liver, not burning fat from storage cells.

The ApoE E4 isoform is deleterious to longevity, while the E2 isoform is protective, with the E4 allele conferring up to an 8-15 fold increased risk for Alzheimer's disease and premature death from age-related conditions.

If you carry the ApoE E4 allele, your genetic risk for Alzheimer's and cardiovascular disease is significantly higher. This genotype is associated with lower odds of reaching extreme old age. Focus on aggressive management of cardiovascular risk factors (lipids, blood pressure) and cognitive health, as these are the pathways through which E4 impacts longevity.

Pharmacological inhibition of de novo ceramide synthesis using myriocin reduces hepatic steatosis, atherosclerosis, and insulin resistance in diet-induced NAFLD models by normalizing ApoB production and enhancing HDL turnover.

This research suggests that high levels of ceramides, often elevated in fatty liver disease, drive cardiovascular risk by increasing bad cholesterol production (ApoB) and slowing down good cholesterol clearance (HDL). While myriocin is not a consumer supplement, the mechanism implies that dietary strategies reducing saturated fat intake and improving insulin sensitivity may lower ceramide levels, thereby protecting against liver and heart disease.

In individuals with type 2 diabetes, hepatic energy metabolism (specifically ATP and inorganic phosphate concentrations) is impaired and correlates with hepatic insulin resistance, independent of liver fat content.

For those with Type 2 Diabetes, liver health involves more than just fat storage; it involves cellular energy production. Research indicates that even when liver fat levels are similar to non-diabetics, people with T2DM have significantly lower levels of cellular energy (ATP) in the liver, which drives insulin resistance. This suggests that supporting mitochondrial health and energy metabolism is a key target for managing T2DM, potentially preceding or existing independently of visible liver fat.

Interleukin-6 (IL-6) secreted by brown adipose tissue is required for the insulin-sensitizing effects of BAT transplantation, acting as a key 'batokine'.

This finding highlights the complexity of metabolic signaling. While exercise and cold exposure increase IL-6, its source and context determine its effect. BAT-derived IL-6 improves insulin sensitivity, whereas chronic elevation in obesity may contribute to resistance. Focus on activating BAT through cold exposure to harness these beneficial hormonal effects.

Exogenous administration of the weak androgen nandrolone decanoate (ND) to obese postmenopausal women undergoing weight loss increases lean body mass and preferentially reduces subcutaneous abdominal fat, but significantly worsens the lipid profile (increased LDL, decreased HDL).

For obese postmenopausal women, using nandrolone decanoate during weight loss can help preserve or build muscle and reduce subcutaneous belly fat. However, this comes with a significant trade-off: it worsens cholesterol levels (lowering 'good' HDL and raising 'bad' LDL). Given these cardiovascular risks, this treatment is not recommended for this population despite the body composition benefits.

Antiandrogen treatment with spironolactone (SP) in obese postmenopausal women undergoing weight loss results in a smaller loss of subcutaneous abdominal fat compared to placebo, with no significant improvement in visceral fat loss.

Taking spironolactone (75mg daily) during weight loss does not appear to offer any advantage in fat loss or body composition for obese postmenopausal women compared to diet alone. It may even result in less total fat loss.

Obese individuals exhibit a diminished endogenous postprandial Peptide YY (PYY) response compared to lean individuals, despite consuming more calories.

If you are obese, your body may not produce enough PYY after meals to signal fullness effectively, making it harder to stop eating. This is a biological reality, not a lack of willpower. Strategies that support gut health and satiety signaling are important, but recognizing this biological barrier can reduce self-blame and help in seeking appropriate interventions.

Protein restriction, specifically methionine restriction, increases maximum lifespan in rodents by approximately 20%, potentially accounting for half of the life-extending effects of caloric restriction.

While animal studies show that restricting protein, especially methionine, can extend lifespan, this is not yet recommended for humans. More research is needed to determine if this is safe or beneficial for people.

Ghrelin is an endogenous peptide hormone that stimulates food intake and growth hormone secretion, with its circulating levels inversely correlated with energy balance (increasing during fasting/starvation and decreasing during feeding/obesity).

Understand that hunger is biologically regulated by ghrelin, which rises when you are fasting or have low energy stores and falls after eating. In obesity, this system is often blunted, with lower baseline ghrelin levels, which may contribute to the difficulty in regulating food intake. Recognizing this hormonal drive can help separate biological hunger from emotional or habitual eating.

Ghrelin stimulates food intake and growth hormone release primarily through the vagus nerve and hypothalamic pathways (NPY/AgRP neurons), rather than solely by crossing the blood-brain barrier.

This mechanism suggests that gut health and vagal nerve integrity may influence hunger signals. While not directly actionable for most, it highlights that hunger signals are complex neural communications, not just simple blood chemistry.

Aging is characterized by a loss of structural and functional complexity in physiological systems, which impairs adaptability and leads to disease.

View aging not just as damage accumulation, but as a loss of system flexibility. Maintaining diverse physical and cognitive challenges may help preserve the 'complexity' that protects against sudden health failures.

Perceived age, derived from facial photographs, is a robust biomarker of biological aging that predicts survival in individuals aged 70 and older, independent of chronological age, sex, and physical/cognitive functioning.

For adults over 70, how you look relative to your peers may be a stronger predictor of how long you will live than your birth date. This does not mean you should obsess over wrinkles, but it suggests that factors influencing facial aging (sun exposure, smoking, stress, social engagement) are deeply linked to your overall biological health and mortality risk. Regular health check-ups that assess functional status (strength, cognition) alongside appearance may provide a more complete picture of your biological age than chronological age alone.

Klotho protein functions as an anti-aging agent by inhibiting four major aging pathways (TGF-β, IGF-1, Wnt, NF-κB) and promoting antioxidant defenses, with deficiency leading to accelerated aging phenotypes and overexpression extending lifespan.

Maintaining healthy kidney function and managing metabolic health (blood sugar, blood pressure) may help preserve natural Klotho levels, which are linked to longevity. While direct Klotho supplementation is not yet a standard consumer intervention, lifestyle factors that support kidney health and reduce inflammation (like exercise and certain diets) are associated with higher Klotho expression.

Aging causes a progressive decline in brown adipose tissue (BAT) mass and thermogenic activity, primarily through mitochondrial dysfunction, reduced sympathetic nervous system stimulation, and hormonal shifts, leading to age-related metabolic alterations.

As you age, your body's ability to burn fat for heat (via brown fat) naturally declines due to changes in hormones, nerve signals, and cell health. This contributes to weight gain and metabolic issues. While you can't stop aging, understanding this process highlights the importance of maintaining metabolic health through lifestyle factors that may support remaining brown fat function, such as staying active and managing stress/hormonal health.

Beige adipose tissue formation declines with age due to defective progenitor cell proliferation and differentiation, potentially linked to changes in the adipose tissue microenvironment and reduced SIRT1 levels.

Your body's ability to create 'beige fat' (fat that burns energy) decreases as you age, partly because the stem cells that make it become less active. This is linked to changes in your body's internal environment and signaling molecules. While this decline is natural, it underscores the importance of maintaining overall metabolic health to support any remaining thermogenic capacity.