Browse the evidence

Resting metabolic rate (RMR) reduction following weight loss is driven primarily by the loss of adipose tissue mass and metabolic adaptations, rather than the loss of skeletal muscle mass.

You don't need to obsess over preserving every gram of muscle to stop your metabolism from slowing down. Research shows that losing fat mass itself, along with hormonal shifts (like lower leptin and thyroid hormones), is what actually drives your resting metabolic rate down after weight loss. This means metabolic adaptation is a natural response to losing fat, not just a failure to build muscle. To manage this, focus on sustainable, slower weight loss and personalized strategies that address these hormonal changes, rather than just trying to 'save' muscle.

Loss of the oxygen sensor PHD1 reduces muscle mass by impairing the stability of the leucine sensor LRS, thereby blunting mTORC1 activation specifically in response to leucine.

Maintaining healthy cellular oxygen sensing and nutrient sensor stability (specifically PHD1 and LRS) is crucial for your muscles to respond to protein/leucine intake. This mechanism explains why older adults often experience 'anabolic resistance'—their muscles struggle to build mass from protein because these specific sensors degrade. While you cannot directly 'dose' PHD1, ensuring adequate oxygenation and avoiding chronic metabolic stress may help preserve these sensors.

Chronic low-grade inflammation, driven by obesity and ectopic lipid deposition, impairs insulin signaling and beta-cell function through pathways like NF-κB, JNK, and oxidative stress.

Inflammation is not just a symptom of diabetes; it is a cause. Excess fat, especially around organs (ectopic fat), triggers inflammation that blocks insulin from working and damages insulin-producing cells. Managing weight and diet reduces this inflammation.

Type 2 diabetes negates the natural cardiovascular protection typically afforded to premenopausal women, resulting in a 25–50% greater excess risk of incident cardiovascular disease in women compared to men with diabetes.

If you have type 2 diabetes, your risk of heart disease is not lower than a man's, even if you are a woman. Diabetes removes the natural heart protection women usually have. You need to manage blood pressure, lipids, and blood sugar as aggressively as a man would to protect your heart.

Females have higher rates of insulin resistance than males from early childhood through mid-puberty, whereas males exhibit greater insulin resistance during late puberty and adulthood.

Insulin resistance changes differently for boys and girls as they grow. Girls tend to be more insulin resistant during early puberty, while boys become more resistant later. This biological difference contributes to why girls are more prone to type 2 diabetes in youth, while men are more prone in midlife.

A high Triglyceride-Glucose (TyG) index is positively associated with a higher prevalence of symptomatic coronary artery disease (CAD) in secondary care patients, independent of social, clinical, and behavioral risk factors.

If you are in secondary cardiac care, ask your doctor about your Triglyceride-Glucose (TyG) index. It is a calculated marker of insulin resistance derived from your fasting triglycerides and glucose levels. A high TyG index is a strong predictor of symptomatic heart disease, even if your standard cholesterol numbers look acceptable. Managing this index through lifestyle changes (diet and activity) is crucial for reducing cardiac risk.

Ketogenic diets increase LDL cholesterol and total cholesterol, which may accelerate atherosclerosis and increase cardiovascular disease risk, despite improving triglycerides and HDL.

Monitor your LDL cholesterol closely when starting a ketogenic diet. While your triglycerides may drop and HDL rise, your LDL may increase significantly. If you have a history of cardiovascular disease or high baseline LDL, consult your provider, as this increase may pose a risk. Consider shifting fat sources to plant-based options (nuts, vegetables) to potentially mitigate LDL elevation.

GIP promotes lipogenesis (fat storage) in adipose tissue, while GLP-1 promotes lipolysis (fat breakdown) indirectly via sympathetic nervous system activation.

GIP helps store fat in adipose tissue, while GLP-1 helps break it down. Dual agonists balance these effects to improve overall metabolic health.

Menstrual cycle phase does not appreciably influence acute strength performance or chronic adaptations (strength/hypertrophy) to resistance exercise training in naturally cycling women.

Do not restrict your training volume, intensity, or frequency based on your menstrual cycle phase. The current scientific consensus indicates that hormonal fluctuations across the cycle do not significantly impact your ability to build strength or muscle. Focus on consistent, high-quality resistance training regardless of where you are in your cycle. If you experience menstrual symptoms that affect your well-being, adjust for comfort, not for perceived biological incapacity.

Systemic inflammation and HPA-axis dysregulation are biological mechanisms mediating the link between high body weight and psychological distress.

Understand that biological factors like inflammation and stress hormone dysregulation contribute to the link between obesity and depression. This is not just 'in your head' but has a physical basis.

Bariatric surgery induces early, pronounced improvements in hepatic and peripheral insulin sensitivity and glycemic control that occur independently of significant weight loss, primarily through anatomical remodeling of the gastrointestinal tract.

If you have severe obesity and type 2 diabetes, bariatric surgery can resolve your diabetes through hormonal changes in your gut, not just by making you smaller. This happens quickly, often before you lose much weight. Consult a multidisciplinary unit to see if you are a candidate.

GLP-1 receptor agonists (specifically liraglutide and dulaglutide) are associated with a statistically significant increase in the risk of overall thyroid disorders compared to placebo or other interventions, although they do not significantly increase the risk of specific conditions like thyroid cancer, hyperthyroidism, or hypothyroidism.

If you are taking a GLP-1 medication like liraglutide or dulaglutide, be aware that there is a slightly higher statistical risk of developing 'overall thyroid disorders' compared to those not taking the drug. However, this does not appear to increase your risk of thyroid cancer or major thyroid dysfunction. Standard monitoring is advised, but the fear of cancer based on animal studies is not supported by large human clinical trials.

Among specific GLP-1 receptor agonists, liraglutide and dulaglutide show a statistically significant increase in the risk of overall thyroid disorders, whereas semaglutide, lixisenatide, and exenatide do not show a significant effect.

Not all GLP-1 medications affect the thyroid equally. If you are concerned about thyroid health, liraglutide and dulaglutide have shown a statistically significant increase in overall thyroid disorders in large trials, whereas semaglutide, lixisenatide, and exenatide have not shown this significant risk. Discuss these differences with your provider when choosing a specific agent.

Tirzepatide requires GIP receptor (GIPR) activation to stimulate insulin secretion in human islets, as blocking GIPR consistently reduces this response.

Tirzepatide's effectiveness in lowering blood sugar relies on its ability to activate the GIP receptor, not just the GLP-1 receptor. In human tissue, blocking the GIP receptor stops tirzepatide from stimulating insulin, proving this second pathway is essential for its full benefit.

Tirzepatide stimulates glucagon secretion in human islets primarily through GIP receptor activation, which overrides the glucagon-suppressing effect of GLP-1 receptor activation.

Tirzepatide increases glucagon secretion via the GIP receptor, which might seem counterintuitive for a diabetes drug. However, this is a normal physiological response to nutrient sensing, and the drug's overall effect is still a significant reduction in blood glucose due to its powerful insulin-stimulating effects.

Tirzepatide stimulates insulin secretion in mouse islets predominantly through the GLP-1 receptor, with minimal GIP receptor contribution at therapeutic doses.

Research on tirzepatide using mice may not fully reflect how it works in humans, as mice require much higher doses for GIP receptor activation. This highlights the importance of human-specific studies for understanding the drug's full mechanism.

Treatment with GLP-1 receptor agonists (specifically Liraglutide and Semaglutide) is associated with a significantly increased risk of developing psychiatric disorders, including major depression, anxiety, and suicidal behavior, in patients with obesity.

If you are taking or considering GLP-1 medications like Ozempic or Wegovy for obesity, be aware that studies link these drugs to a higher risk of depression, anxiety, and suicidal thoughts, especially with long-term use. Discuss your mental health history with your doctor before starting, and monitor your mood closely. If you experience worsening depression or suicidal thoughts, contact your healthcare provider immediately.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is strongly associated with increased subclinical atherosclerosis (measured by carotid intima-media thickness and coronary artery calcification) and incident cardiovascular events, but does not independently increase cardiovascular mortality risk after adjusting for confounders.

If you have MASLD, prioritize cardiovascular risk management (blood pressure, lipids, glucose) as aggressively as you manage your liver health. Your risk of heart events is elevated, but your risk of dying from liver failure is lower than dying from heart disease. Comprehensive cardiometabolic risk management is warranted.

L-cells are not a homogeneous population; they are anatomically heterogeneous, with proximal (duodenal/jejunal) L-cells primarily secreting GLP-1 in response to macronutrients, while distal (ileal/colonic) L-cells co-secrete PYY and respond to microbial metabolites like SCFAs and bile acids.

Your gut's hormonal response to food depends on where the food is absorbed. Eating fiber and fats that reach the lower intestine (via fermentation or specific fats) stimulates different hormones (like PYY) than eating simple sugars in the upper intestine. A diverse diet that reaches different parts of the gut may optimize this hormonal signaling better than focusing on a single nutrient type.

Higher circulating concentrations of fatty acids produced via de novo lipogenesis (specifically 16:0, 16:1n7, and 18:0) are positively associated with an increased incidence of type 2 diabetes.

High levels of certain fats produced by your body (de novo lipogenesis) from carbs and alcohol are linked to a higher risk of type 2 diabetes. This suggests that managing carbohydrate and alcohol intake may help regulate these specific internal fat pathways, potentially lowering diabetes risk, independent of overall body weight.

The association between oleic acid (18:1n9) and type 2 diabetes risk is attenuated to non-significance when adjusted for triglycerides and palmitic acid (16:0), suggesting its risk is dependent on overall de novo lipogenesis activity rather than being an independent driver.

While high levels of some fats made by your body are linked to diabetes, the link for oleic acid (found in olive oil) disappears when you account for overall metabolic health markers like triglycerides. This implies that focusing on the broader metabolic context (carb/alcohol intake) is more important than demonizing specific fats like oleic acid.

Deletion or inhibition of MKK6 in white adipose tissue increases energy expenditure and protects against diet-induced obesity and diabetes by enhancing thyroid hormone (T3)-mediated browning of white fat.

This research suggests that blocking MKK6 in fat tissue could help treat obesity by making fat burn more energy, similar to brown fat. While not a current human treatment, it highlights thyroid hormone sensitivity and fat metabolism as key targets for future obesity drugs.

Enteroendocrine cells (EECs) regulate the gut-brain axis through two distinct mechanisms: slow endocrine hormone release into the bloodstream and rapid synaptic signaling via neuropod cells.

Your gut has a direct 'phone line' to your brain. Foods trigger specific cells (EECs) that send signals either slowly through hormones or instantly through nerves. This is why drugs like semaglutide (Ozempic) work—they amplify these natural signals to regulate hunger and blood sugar. Understanding this helps explain why gut health directly impacts mood and metabolism.

Neuropod cells communicate nutrient information to the vagus nerve primarily via glutamate release, allowing for rapid distinction between sugar and artificial sweeteners.

Your gut has a specific 'sugar detector' (neuropod cells) that sends a fast signal to your brain using glutamate. This signal is triggered by real sugar (sucrose) but not by artificial sweeteners. This might explain why artificial sweeteners don't always satisfy sugar cravings or trigger the same metabolic responses as real sugar.