Browse the evidence

Ghrelin acts as an orexigenic signal by binding to GHSR on AgRP neurons in the arcuate nucleus, stimulating NPY and AGRP expression and increasing food intake and adiposity.

Ghrelin is your body's 'hunger hormone,' released by the stomach when empty. It signals the brain to eat. In obesity, ghrelin levels are often lower than expected, yet hunger persists, suggesting complex brain resistance. Understanding that hunger is a normal signal helps distinguish between physical need and emotional eating.

GLP1, secreted from intestinal L-cells after meals, acts as an anorexigenic signal by activating GLP1 receptors in the hypothalamus and brainstem, inhibiting food intake via vagal afferents and central circuits.

GLP-1 is a hormone your gut releases after eating to help you feel full. Modern medications mimic this hormone to enhance its effect, leading to reduced appetite and weight loss. This works by acting on both the gut nerves and the brain.

Central administration of Neuropeptide Y (NPY) acts as a potent orexigenic signal that stimulates food intake, specifically increasing carbohydrate preference, reducing the latency to eat, and delaying satiety to augment meal size.

Neuropeptide Y (NPY) is a brain chemical that strongly drives hunger, specifically for carbohydrates. It works by making you start eating sooner, motivating you to work harder for food, and making you feel full later than usual, leading to larger meals. This is a central brain mechanism, not triggered by eating NPY from food.

Defective lipid storage capacity in white adipose tissue, often due to impaired expansion or PLIN dysfunction, leads to ectopic fat deposition in non-adipose tissues, causing insulin resistance and type 2 diabetes.

Your body relies on fat cells (adipose tissue) to safely store excess energy. If these cells cannot expand or function properly (due to genetics or chronic overloading), fat spills over into organs like the liver and muscles. This 'spillover' causes insulin resistance and type 2 diabetes. Therefore, maintaining healthy fat cell function is as important as reducing total fat mass.

AgRP neurons promote feeding and inhibit energy expenditure by antagonizing MC4R, and their activity is increased during fasting/starvation.

During fasting, your body activates AgRP neurons to drive hunger and conserve energy. This is a normal survival mechanism. Understanding this helps explain why hunger increases when you restrict calories.

Rosiglitazone, a thiazolidinedione that increases insulin sensitivity by activating PPAR-gamma, delays monotherapy failure and preserves beta-cell function more effectively than metformin or glyburide in patients with recently diagnosed type 2 diabetes.

For newly diagnosed type 2 diabetics, rosiglitazone (8mg/day) may offer better long-term preservation of the pancreas's ability to produce insulin compared to metformin or glyburide, potentially delaying the need for additional medications. This benefit comes with the trade-off of potential side effects like weight gain or fluid retention, which should be monitored.

Continuous Positive Airway Pressure (CPAP) therapy for Obstructive Sleep Apnoea (OSA) results in a statistically significant, albeit small, increase in body weight and Body Mass Index (BMI) compared to control conditions.

If you start CPAP for sleep apnea, expect a small amount of weight gain (average ~0.4 kg in the studies, but variable). This is likely because your body is no longer burning extra energy fighting breathing interruptions and your sleep hormones (growth hormone/cortisol) are normalizing. To counter this, proactively combine CPAP with standard weight management strategies like diet and exercise, rather than stopping CPAP.

Hedonic feeding is driven by the mesolimbic dopaminergic system (specifically 'wanting'), which can override homeostatic satiety signals.

Your brain is wired to seek pleasure from palatable food via dopamine release, which can override signals of fullness. This is an evolutionary adaptation, not a moral failing. Understanding that 'wanting' (motivation) is distinct from 'liking' (pleasure) helps explain why you might crave food even when not hungry.

Semaglutide (both oral and subcutaneous formulations) is associated with a high incidence of mild-to-moderate, transient gastrointestinal adverse effects (nausea, vomiting, diarrhea), which are dose-dependent and time-dependent, occurring primarily during the initial 8-12 weeks of treatment.

If you start semaglutide, expect some nausea, vomiting, or diarrhea, especially in the first few months. This is common and usually gets better. To minimize this, start with the lowest dose and follow the doctor's schedule for increasing it slowly. Eat smaller, slower meals and avoid fatty foods. If you take the oral version, take it on an empty stomach with a small sip of water, waiting 30 minutes before eating or drinking anything else.

Semaglutide does not significantly increase the risk of hypoglycemia in patients not using concomitant insulin or sulfonylureas, due to its glucose-dependent mechanism of action.

You don't need to worry about your blood sugar dropping dangerously low while taking semaglutide by itself. It works gently with your body's natural processes. However, if you are also taking insulin or sulfonylureas, your risk of low blood sugar increases, so your doctor may lower the dose of those other medications.

Adiponectin, secreted by healthy PVAT, acts as a vasodilator by activating AdipoR1 receptors, stimulating AMPK and eNOS to produce nitric oxide, thereby lowering blood pressure and improving insulin sensitivity.

Maintaining healthy adipose tissue function is crucial. While direct adiponectin supplementation is not discussed as a standard therapy, lifestyle interventions that improve adipose tissue health (like exercise and weight loss) naturally boost adiponectin levels, aiding blood pressure control and insulin sensitivity.

Leptin regulates energy balance by acting on a dispersed neuronal network in the hypothalamus, specifically activating anorexigenic POMC neurons and inhibiting orexigenic NPY/AgRP neurons in the arcuate nucleus.

Leptin works by turning 'off' hunger neurons (NPY/AgRP) and 'on' fullness neurons (POMC). In obesity, this specific circuitry in the brain's arcuate nucleus becomes resistant to the signal.

Exogenous leptin administration effectively treats obesity and metabolic disease in patients with congenital leptin deficiency or generalized lipodystrophy, but is largely ineffective as a monotherapy for common obesity due to leptin resistance.

If you have a rare genetic condition causing leptin deficiency or generalized lipodystrophy, leptin therapy is a highly effective, approved treatment that can restore metabolism and fertility. However, for the vast majority of people with common obesity, leptin levels are already high, and the body has become resistant to it. Taking leptin alone will likely not work; current research suggests combining it with other agents like amylin may be necessary to achieve significant weight loss.

Leptin acts as a critical afferent signal in a negative feedback loop that maintains homeostatic control of adipose tissue mass, protecting against both starvation and obesity.

Your body uses leptin, a hormone from fat cells, to tell your brain how much energy you have stored. This is a biological safety system, not a choice. Understanding this helps explain why weight loss is difficult and why the body fights back against weight loss—it is trying to maintain homeostasis.

Testosterone treatment in older men with low testosterone increases volumetric bone mineral density and estimated bone strength, but does not significantly improve areal bone mineral density.

If you are an older man with confirmed low testosterone, testosterone therapy can significantly improve your bone density and bone strength, particularly in the spine. The treatment involves daily application of a gel, with dose adjustments to keep levels in the normal range for young men. While long-term safety requires more data, this study found no increase in cardiovascular or prostate issues over one year.

Endogenous glucocorticoids drive skeletal muscle atrophy by upregulating muscle-specific E3 ubiquitin ligases (MuRF1 and MAFbx) and suppressing protein synthesis via mTOR inhibition, a process mediated by the HPA axis activation during chronic inflammation or stress.

Chronic stress and inflammation trigger hormones (glucocorticoids) that actively break down muscle protein and stop new muscle building. To mitigate this, managing underlying inflammatory conditions and stress is as important as nutrition and training, as the hormonal environment directly dictates muscle retention.

Obesity results from dysregulation of the hypothalamic melanocortin system, where antagonists like AgRP block the anorexic effects of insulin and leptin.

Your brain has a 'thermostat' for fat (melanocortin system). If this system is disrupted (genetically or by obesity itself), your brain fights weight loss. Understanding this helps explain why dieting is hard and why medical interventions targeting this system can be effective.

Insulin resistance is a central mechanism in Metabolic Syndrome, driven by impaired insulin signaling pathways (PI3K/Akt) and exacerbated by factors like saturated fatty acids, oxidative stress, and chronic inflammation.

Metabolic Syndrome is largely driven by insulin resistance, where your body's cells don't respond well to insulin. This leads to high blood sugar, fat storage, and other issues. Managing this involves addressing the root causes of insulin resistance through diet, exercise, and weight management.

Metabolic syndrome is fundamentally a chronic inflammatory state driven by immune system deregulation, specifically involving M1 macrophages and pro-inflammatory cytokines (TNF-alpha, IL-1beta) originating from adipose tissue, liver, and intestine.

Think of your fat tissue not just as stored energy, but as an active organ that sends out distress signals (inflammation) when it's overstuffed. These signals damage your blood vessels and block insulin. Managing your weight and staying active directly calms this immune response, protecting your heart and metabolic health.

Type 2 diabetes pathogenesis requires the concurrent presence of both insulin resistance and beta-cell dysfunction, as neither defect alone is typically sufficient to cause overt glucose intolerance.

Managing Type 2 Diabetes requires addressing both how your body uses insulin (resistance) and how much insulin your pancreas can produce (secretion). Lifestyle changes that improve insulin sensitivity (like exercise and weight loss) are crucial, but they may not be enough if beta-cell function has significantly declined, often requiring medical intervention to support secretion or sensitivity.

Mutations in the human MC4 receptor are a common cause of severe childhood obesity, characterized by hyperphagia, increased linear growth, and hyperinsulinemia.

For some individuals, especially children with severe obesity, the root cause is a genetic mutation in the MC4 receptor. This leads to extreme hunger and rapid growth. Understanding this genetic basis is crucial for selecting appropriate treatments, as standard approaches may fail.

Tirzepatide is associated with a higher incidence of gastrointestinal adverse events (nausea, vomiting, diarrhea) compared to placebo and basal insulin, which can lead to treatment discontinuation.

Tirzepatide often causes stomach problems like nausea, vomiting, and diarrhea, especially at higher doses (10mg and 15mg). These side effects are more common than with placebo or basal insulin and can cause some people to stop taking the medication. Starting at a lower dose and increasing slowly may help.

Genetic variants at the SHBG locus and multiple other loci (including GCKR, LHCGR, and UGT2B15) significantly influence circulating sex hormone-binding globulin (SHBG) concentrations, with effects that are often sex-differentiated.

Your SHBG levels are partly determined by your DNA, specifically variants near genes like SHBG, GCKR, and LHCGR. This genetic background influences how your body handles testosterone and estrogen. While you cannot change your genetics, this knowledge highlights why SHBG is a critical marker for metabolic health and hormone-sensitive cancer risk.

Orexin neurons regulate wakefulness by exciting monoaminergic and cholinergic neurons in the hypothalamus and brain stem, maintaining consolidated wake periods.

Maintaining a healthy lifestyle that supports orexin function may help regulate sleep-wake cycles. This includes regular exercise, stress management, and adequate nutrition.