Browse the evidence

Lower Free T4 (FT4) levels within the euthyroid range are negatively associated with BMI, waist circumference, and triglycerides, and positively associated with HDL-cholesterol.

While T3 is often the focus, your Free T4 levels also matter. In this study, lower FT4 (within the normal range) was linked to lower body weight and waist size. This highlights that thyroid health is about the balance and ratio of hormones, not just hitting a 'normal' TSH number.

Higher TSH levels within the normal reference range are positively associated with total cholesterol, triglycerides, and blood pressure.

If your TSH is on the higher end of the 'normal' range, it might be contributing to higher blood pressure and cholesterol, even if you don't have hypothyroidism. This suggests that 'normal' TSH might not be 'optimal' for everyone, especially regarding cardiovascular health.

Performing intense aerobic exercise prior to resistance training does not compromise muscle hypertrophy or strength gains and may actually enhance muscle volume increases compared to resistance training alone.

If you want to build muscle and improve cardiovascular health, you can do cardio before your weight training without worrying about losing muscle gains. In fact, this study suggests you might actually build more muscle volume by doing so. Just make sure to wait about 6 hours between your cardio and weight sessions, and perform the cardio intensely enough to challenge yourself.

Higher velocity loss thresholds (20% and 40%) during resistance training maximize muscle hypertrophy compared to lower thresholds (0% and 10%), but excessive velocity loss (40%) induces negative neuromuscular adaptations such as slowed contraction delay and reduced early rate of force development.

For muscle growth, stop your sets when your bar speed drops by about 20% from your fastest rep. This gives you the best hypertrophy benefits without slowing down your muscle's ability to produce force quickly. Avoid stopping sets when speed drops by 40%, as this can hurt your power output. For strength, any moderate velocity loss (10-20%) works well, so prioritize technique and speed over total volume.

Monitoring accumulated training and match load in football is essential for controlling training demands, optimizing physiological adaptations, and guiding individual athlete performance, yet no consensus exists on the most effective monitoring system or metrics.

Track both external load (distance, speed zones via GPS) and internal load (heart rate, sRPE) across the entire week, not just match days. Since there is no single 'best' metric, consistency in how you measure load week-to-week is more important than the specific device used. Focus on the cumulative effect of training sessions, which make up 80% of the weekly load, to guide individual performance.

Saturated fatty acids (SFAs) promote inflammation and insulin resistance by activating the NLRP3 inflammasome and NF-κB pathways, whereas unsaturated fatty acids (UFAs) like EPA/DHA can inhibit these pathways.

The type of fat you eat matters for inflammation. Saturated fats (like palmitate) can trigger inflammatory pathways (NLRP3) and worsen insulin resistance. In contrast, unsaturated fats, particularly omega-3s (EPA/DHA), can help prevent this inflammation. Prioritize unsaturated fats for metabolic health.

BCAAs can stimulate mitochondrial biogenesis via the eNOS/NO/SIRT1/PGC-1α and mTOR/YY1 pathways, but this effect is tissue-specific and can be overridden by high levels of saturated fatty acids which suppress PGC-1α.

BCAAs can support mitochondrial health by stimulating biogenesis pathways, but this benefit can be canceled out by a diet high in saturated fats. To support mitochondrial function, combine BCAA intake (or natural sources) with a balanced diet low in saturated fats.

Semaglutide at its maximum tolerated dose (MTD) is associated with the highest odds of treatment discontinuation due to adverse events among all tested regimens, including tirzepatide MTD.

If you choose semaglutide at its maximum dose, be aware that you have the highest statistical risk of stopping the medication due to side effects compared to other options in this study. Monitor your tolerance closely and communicate with your provider immediately if side effects become unmanageable.

Tirzepatide demonstrates cardiovascular safety, with hazard ratios for major adverse cardiovascular events (MACE) remaining below 1.3 compared to pooled comparators, indicating no increased cardiovascular risk.

For patients with heart disease or high risk factors, Tirzepatide has been shown to be safe regarding cardiovascular events. It does not increase the risk of heart attack, stroke, or cardiovascular death compared to standard treatments. This makes it a viable option for those who need effective diabetes management without compromising heart health.

Increasing meal frequency (3 meals + 3 snacks daily) does not promote greater weight loss, fat loss, or appetite control compared to a lower meal frequency (3 meals daily) when total energy intake is equated.

If you are trying to lose weight, you do not need to force yourself to eat 6 small meals a day. Whether you choose to eat 3 meals or 3 meals plus 3 snacks, your weight loss will be the same as long as you consume the same total calories. Choose the pattern that best fits your lifestyle and hunger cues without exceeding your calorie target.

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.

Diet order effects on energy balance and body composition are not observed when comparing Ultra-Processed Foods (UPF) to Minimally Processed Foods (MPF) if the diets are matched for macronutrients, energy density, and fiber.

When comparing ultra-processed foods to minimally processed foods, the physical properties of the food (energy density, fiber, volume) matter more than the processing status itself for determining intake. In this study, when UPF and MPF were matched for these properties, there was no difference in weight loss or energy intake based on which diet was eaten first. This suggests that formulating UPF to match the fiber and density of whole foods may mitigate overeating behaviors.

Early Time-Restricted Eating (eTRE) with an 8-hour window (8 am - 4 pm) does NOT produce significantly greater weight loss than a calorie-restricted Mediterranean diet (MedDiet) in adults with obesity.

Early time-restricted eating (8 am - 4 pm) with a 600-calorie deficit did not result in significantly greater weight loss than a standard Mediterranean diet in this study. You may not see extra benefits from this specific timing strategy.

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.

Caloric restriction (CR) attenuates the age-associated increase in Ink4a/Arf expression in specific tissues (kidney, ovary, heart, testis), correlating with reduced pathology and extended longevity.

Caloric restriction can reduce the expression of aging-related genes like p16INK4a in certain organs (kidney, heart, etc.), which is linked to reduced disease. This suggests that managing calorie intake may help slow biological aging in specific tissues, although the effect is not uniform across all organs.

The food industry actively undermines public health dietary advice and government nutrition guidelines to protect market share for processed, calorie-dense products.

Be skeptical of health claims on processed food packaging. Recognize that marketing strategies are designed to increase consumption, not necessarily to improve health. Prioritize whole, unprocessed foods and read ingredient lists critically.

Food industry lobbying and legal strategies have successfully deregulated dietary supplements and weakened the FDA's ability to restrict false health claims.

Do not assume supplements are proven to work just because they are sold in stores. Look for third-party verification seals and consult a healthcare provider before starting any new supplement regimen.

Variability in resting skeletal muscle metabolism is a major determinant of interindividual differences in resting energy expenditure (BMR and SMR), independent of body composition.

Your resting metabolic rate isn't just about how much muscle you have, but how metabolically active that muscle is. People with 'low' metabolic rates may be predisposed to weight gain. While you cannot easily change your genetics, understanding that muscle metabolism varies among individuals highlights why standard calorie predictions often fail for some people.

Dietary supplements are generally safe and pose significantly lower risks of adverse events, hospitalizations, and fatalities compared to prescription drugs and even common foods.

You do not need to fear that taking a standard dietary supplement will cause you to end up in the emergency room or suffer a fatal outcome. The data shows that serious adverse events from supplements are extremely rare compared to prescription medications and even foodborne illnesses. However, you should still choose products from reputable manufacturers that undergo third-party testing (like NSF or Informed Choice) to ensure purity and avoid adulterated products.

Chronic overexpression of melanin-concentrating hormone (MCH) in the lateral hypothalamus causes obesity and insulin resistance, with the severity and onset dependent on genetic background and dietary fat intake.

This research highlights that neuropeptides like MCH play a crucial role in regulating hunger and metabolism. While you cannot directly control MCH levels, understanding that your brain's signaling for hunger is biologically driven can help separate 'willpower' issues from physiological signals. The study also underscores that genetic predispositions to obesity can be mitigated or exacerbated by diet quality (specifically fat content) and that individual biological responses vary significantly.

Global average consumption of sugar-sweetened beverages (SSBs) in adults is approximately 0.58 servings (8 oz) per day, with significant regional and demographic heterogeneity, where consumption is highest in younger adults and specific regions like the Caribbean.

Track your sugar-sweetened beverage intake, as the global average is nearly half a serving (8 oz) per day. Be aware that younger adults and those in high-consumption regions (like the Caribbean) drink significantly more. Reducing SSBs is a primary lever for improving metabolic health, alongside managing fruit juice which, despite being 'natural,' contributes to sugar load and dental issues.

Milk consumption is highest in older adults and specific regions (Central Latin America, Europe), while fruit juice consumption is highest in Australasia and high-income North America, with all three beverage categories being lowest in East Asia and Oceania.

If you are older, you likely consume more milk, which is a key source of calcium and vitamin D. If you live in East Asia or Oceania, your intake of all major non-alcoholic caloric beverages (SSBs, juice, milk) is among the lowest globally. Adjust your intake based on regional norms and age-related nutritional needs.

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.

Scientific articles regarding the health effects of soft drinks, juice, and milk that are funded exclusively by the food/beverage industry are significantly more likely to conclude favorably for the sponsor's product compared to articles with no industry funding.

When evaluating health claims about soft drinks, juice, or milk, prioritize research that did not receive funding from the beverage industry. Industry-funded studies are significantly more likely to report favorable health outcomes for the sponsored product, suggesting a high risk of sponsorship bias.