Browse the evidence

Serum 25-hydroxyvitamin D [25(OH)D] is the best indicator of vitamin D nutritional status, reflecting contributions from diet and dermal production, and should be standardized using programs like VDSP.

To check your Vitamin D status, ask for a serum 25-hydroxyvitamin D [25(OH)D] test. This is the gold standard. Ensure your lab participates in standardization programs like VDSP for accurate results.

Obesity (excess body fatness) is a convincing risk factor for at least 13 different cancer sites, including endometrial, postmenopausal breast, colorectal, esophageal, renal, meningioma, pancreatic, gastric cardia, liver, multiple myeloma, ovarian, gallbladder, and thyroid cancers.

Maintain a healthy body weight to reduce cancer risk. Focus on sustainable lifestyle changes like balanced nutrition and regular activity rather than rapid weight loss, as avoiding weight gain is a viable preventive measure.

Higher peak aerobic power (VO2peak) is the primary predictor of long-term survival in men with coronary heart disease, with each 1 mL/kg/min increase reducing mortality risk by 9%.

For men with heart disease, improving aerobic fitness is the single most effective way to extend life. You don't need elite fitness; even small gains in VO2 (measured by how much oxygen you use during peak exercise) significantly lower your risk of dying. Focus on supervised cardiac rehabilitation to safely build this capacity.

In postmenopausal women, higher baseline BMI (specifically ≥35.0) is associated with a significantly increased risk of invasive breast cancer, particularly estrogen receptor-positive subtypes, and is linked to more advanced disease characteristics and higher mortality.

For postmenopausal women, maintaining a healthy weight (BMI < 25) is critical for reducing invasive breast cancer risk, especially estrogen receptor-positive types. While weight loss after becoming obese may not reverse the elevated risk established by high BMI, preventing obesity in the first place is the most effective strategy. Regular screening is essential, as obesity is also linked to more advanced disease stages.

The hazardous effects of sedentary behavior on mortality are more pronounced in physically inactive people, and high levels of moderate-to-vigorous physical activity (MVPA) can attenuate but not fully eliminate the risk associated with high sedentary time.

If you sit a lot, exercise is crucial to mitigate the risk, but it may not fully erase it. Aim for at least 150 minutes of moderate-to-vigorous activity per week, but also try to stand up and move frequently during the day.

Metabolic and bariatric surgery (MBS) is recommended for individuals with BMI >35 kg/m2 regardless of comorbidity status, and for those with BMI 30-34.9 kg/m2 who have metabolic disease or fail nonsurgical treatments.

If your BMI is over 35, surgery is a recommended first-line treatment option, not just a last resort. If your BMI is between 30 and 35, you should still consider surgery, especially if you have diabetes or other metabolic issues, or if lifestyle changes haven't worked. For Asian individuals, the thresholds are lower (BMI >27.5 for surgery consideration).

The absolute mass of n-6 and n-3 fatty acids consumed is more important for cardiovascular health than the n-6/n-3 ratio.

Stop obsessing over the ratio of your vegetable oils to fish oils. Instead, ensure you are eating enough linoleic acid (5-8% of calories) and enough EPA/DHA (500-1000 mg/day). If you meet these absolute targets, the ratio will naturally fall into a healthy range (~6:1).

In women, higher body mass index (BMI ≥27 kg/m²) and significant adult weight gain (≥11 kg from age 18) are strongly associated with an increased risk of ischemic stroke, whereas obesity is inversely associated with hemorrhagic stroke.

For women, maintaining a healthy weight and avoiding significant weight gain from young adulthood are crucial for preventing ischemic stroke. While being lean might slightly increase the risk of hemorrhagic stroke (especially if you smoke or have high blood pressure), the overall risk of ischemic stroke rises sharply with higher BMI and weight gain. Focus on stable, healthy weight management and controlling blood pressure and cholesterol to mitigate these risks.

Visceral fat is more metabolically hazardous than subcutaneous fat because it is more sensitive to lipolytic stimuli and releases free fatty acids directly into the portal vein, leading to hepatic insulin resistance and ectopic fat storage.

Target visceral fat reduction through diet and exercise. This type of fat is more dangerous than subcutaneous fat because it directly impacts liver health and insulin sensitivity.

Self-reported energy intake (EI) is systematically underestimated compared to doubly labelled water (DLW) measured energy expenditure (EE) across diverse populations, including adults, children, and obese individuals.

If you are tracking your food intake for health or fitness, expect that you are likely under-reporting your calories, especially if you are dieting or concerned about body weight. Studies using objective measures like DLW show that self-reported intake is consistently lower than actual expenditure. To get a more accurate picture, consider using objective markers or acknowledging a potential 15-30% gap in your self-reported data.

Obesity is a significant risk factor for the development and severity of various chronic pain conditions, including osteoarthritis, low back pain, and headaches, largely mediated by mechanical loading and systemic inflammation.

Being overweight increases your risk of developing chronic pain, especially in the back, knees, and head. This is due to both the physical weight on your joints and inflammation in your body. Losing weight can reduce this risk and severity of pain.

FGF21 is required for the metabolic and behavioral adaptations to protein restriction, including increased energy expenditure, increased food intake, and reduced body weight gain.

This mechanism is specific to rodents; humans do not have FGF21 knockout models. However, it suggests that FGF21 signaling is a critical link between protein intake and metabolic rate. Low protein intake may blunt metabolic adaptation if FGF21 signaling is impaired.

Individuals with ADHD have a significantly higher prevalence of obesity and overweight compared to those without ADHD, with odds ratios of 1.20 for children and 1.55 for adults.

If you have ADHD, you are statistically more likely to be obese than someone without it, regardless of age. This is not due to medication (which may actually lower risk) but likely due to executive dysfunction affecting eating habits. Screen for obesity as part of ADHD management, and screen for ADHD in obesity cases, especially if weight loss attempts have failed.

Glucose tolerance decreases significantly from morning to evening, resulting in higher postprandial blood glucose levels in the afternoon and evening compared to the morning, driven by reduced insulin sensitivity and secretion.

Your body handles carbohydrates better in the morning. If you eat the same meal in the evening, your blood sugar will spike significantly higher (by 30-50 mg/dl) than if you ate it in the morning, even if you fasted for the same amount of time. Prioritize higher-carb meals earlier in the day to minimize glucose spikes.

Circadian rhythmicity and sleep independently and additively decrease glucose tolerance, with the combined effect of nighttime sleep and circadian timing causing the lowest glucose tolerance of the 24-hour cycle.

Your body's ability to regulate blood sugar drops significantly during sleep, even if you aren't eating. This is due to both the time of day (circadian rhythm) and the act of sleeping itself. Prioritizing good sleep hygiene helps maintain stable glucose levels overnight.

Despite improvements, US adults continue to consume disproportionately high energy from low-quality carbohydrates and saturated fat remains above recommended levels.

Do not assume that 'healthy eating' is complete. Actively monitor and reduce your intake of added sugars and saturated fats, as these remain the primary dietary challenges for the average US adult.

Adherence to a Mediterranean diet increases the abundance of Faecalibacterium prausnitzii and butyrate-producing genes, while decreasing potentially proinflammatory Ruminococcus gnavus, independently of changes in total SCFA concentrations.

Eating a Mediterranean diet changes your gut bacteria to favor beneficial species like Faecalibacterium prausnitzii, which are linked to lower inflammation. This happens even if your total fiber intake doesn't change dramatically, as the *type* of fiber and plant compounds matters.

Physical inactivity is a primary, direct cause of most chronic diseases, acting through distinct biological mechanisms that differ from those of exercise, rather than merely being the absence of exercise.

Stop viewing inactivity as merely 'not exercising.' It is an active biological state that rapidly degrades health (e.g., insulin sensitivity drops within days, vascular function changes immediately). To prevent chronic disease, you must actively counteract inactivity with regular physical activity, as the mechanisms of harm from sitting are distinct from the benefits of exercise.

Excess body weight (BMI ≥ 25 kg/m²) is causally associated with a substantial global cancer burden, accounting for approximately 3.9% of all cancers (544,300 cases) in 2012, with the risk driven by the high prevalence of obesity in high-income countries.

Maintaining a healthy body weight is one of the most effective ways to reduce your risk of developing several types of cancer. This is not just about aesthetics; excess body fat, particularly visceral fat, creates a biological environment that promotes tumor development. Focus on sustainable lifestyle changes that support a healthy weight, especially if you live in or originate from regions with high obesity rates, as the risk scales with the prevalence of excess weight in your population.

Higher degrees of personal clinical support and longer treatment duration in eCBT-I are associated with larger effect sizes, while higher dropout rates are associated with smaller effect sizes.

To get the best results from eCBT-I, choose a program that offers some level of personal support, even if it's just the option to contact staff. Be prepared to commit to the full duration of the program, as longer programs tend to be more effective. Staying engaged and avoiding dropout is crucial for success.

Higher levels of even-chain saturated fatty acids (myristic, palmitic, and stearic acid) in plasma phospholipids are positively associated with an increased risk of incident type 2 diabetes, whereas higher levels of odd-chain (pentadecanoic, heptadecanoic) and long-chain (arachidic, behenic, tricosanoic, lignoceric) saturated fatty acids are inversely associated with type 2 diabetes risk.

Stop treating all saturated fats as the same enemy. The type of fat matters significantly for diabetes risk. High levels of even-chain fats (like palmitic and stearic acid, often linked to processed foods and animal fats) are associated with higher diabetes risk. Conversely, odd-chain fats (like pentadecanoic and heptadecanoic acid, biomarkers for dairy fat) and long-chain fats are associated with lower risk. Focus on the quality and source of your fats rather than just minimizing total saturated fat intake.

Smoking (active and passive) significantly reduces fertility in both men and women, delaying conception and reducing ART success rates, with mechanisms including DNA damage, altered hormone levels, and zona pellucida thickening.

Stop smoking immediately if you are trying to conceive. This applies to both partners. Smoking reduces sperm quality in men and egg quality/hormonal balance in women. It also reduces the success of IVF. Quitting improves your chances of natural conception and ART success.

Subcutaneous white adipose tissue (WAT) expansion is metabolically protective, whereas preferential visceral WAT expansion is associated with increased risk for insulin resistance and metabolic syndrome.

Monitor your waist circumference as a proxy for visceral fat. A high waist-to-hip ratio indicates visceral fat accumulation, which is a stronger risk factor for diabetes and heart disease than overall BMI. Prioritize strategies that favor subcutaneous fat storage or prevent visceral accumulation, such as regular aerobic exercise and stress management.

Dapagliflozin (SGLT2 inhibitor) provides glycemic control equivalent to glipizide (sulfonylurea) while inducing significant weight loss and reducing hypoglycemia risk in type 2 diabetes patients inadequately controlled on metformin.

If you are taking metformin and your blood sugar is not controlled, adding Dapagliflozin can help lower your HbA1c just as effectively as Glipizide, but without the typical side effects of weight gain and low blood sugar. It works by removing excess sugar through urine. Be aware of a slightly higher risk of genital infections, which are usually treatable.