Browse the evidence

Caffeine improves performance in endurance and high-intensity exercise through mechanisms involving reduced perception of fatigue and enhanced central drive, with benefits seen at low doses.

Caffeine can improve performance in endurance and high-intensity sports. Use 2-6 mg per kg of body weight. It works by reducing the perception of fatigue. Be aware of side effects like insomnia or GI distress, especially at higher doses. Habituated users may not experience significant diuretic effects.

Dietary supplements carry a risk of positive doping results due to contamination or inaccurate labeling, and athletes should consult sports nutrition professionals.

Always assume supplements may be contaminated with prohibited substances. Consult a sports nutrition professional. Use third-party tested products. The risk of a positive doping test is real.

Improving the availability of low-calorie beverages in the home environment decreases SSB intake and body weight in adolescents with overweight or obesity.

For families with overweight adolescents who drink a lot of soda, deliver or stock water and diet beverages at home. This simple environmental change has high-certainty evidence for reducing soda intake and body weight.

Supervised exercise interventions significantly improve self-reported quality of life (QoL) and physical function (PF) in patients with cancer during and following treatment, whereas unsupervised exercise does not produce statistically significant benefits for these outcomes.

For cancer patients, supervised exercise programs provide a small but statistically significant boost to quality of life and physical function compared to usual care. If supervision is not possible, unsupervised exercise alone may not significantly improve these self-reported outcomes unless the weekly energy expenditure is kept high. Prioritize supervised programs when available.

Physical exercise improves insulin sensitivity and glucose disposal in skeletal muscle, partly through AMPK activation.

Regular moderate-intensity exercise combined with a healthy diet is the most effective way to prevent type 2 diabetes in high-risk individuals.

Intensive lifestyle modification (ILS) is significantly more effective at preventing type 2 diabetes in older adults (60-85 years) compared to younger adults, primarily due to greater adherence resulting in higher weight loss and physical activity levels.

If you are over 60 and at risk for diabetes, an intensive lifestyle program focusing on moderate exercise (like brisk walking) and modest weight loss (7% of body weight) is highly effective. Older adults in the study actually benefited more than younger ones, likely because they had more time and fewer distractions to stick to the program. Focus on consistency and weight loss rather than high-intensity training.

Doubling the proportion of vegetarian meal options available in a cafeteria from 25% to 50% significantly increases the selection and sales of vegetarian meals while decreasing meat meal sales, with the largest effect observed among diners with the lowest prior levels of vegetarian consumption.

To encourage more plant-based eating in a cafeteria, simply double the number of vegetarian dishes offered relative to meat dishes (e.g., from 1 out of 4 options to 2 out of 4). This simple change in availability significantly increases vegetarian sales, especially among those who rarely eat vegetarian meals, without negatively impacting total sales or causing rebound meat consumption at other meals.

Recurrent sleep restriction and deprivation significantly impair vigilance and neurocognitive function, leading to negative impacts on performance and increased risk of medical errors.

Prioritize sleep duration and quality as a non-negotiable component of performance and safety. Sleep restriction is not a badge of honor; it is a performance-limiting factor that impairs vigilance and increases error risk, comparable to impairment in other domains.

Lifestyle interventions maintaining a carbohydrate-rich diet are safe and effective for preventing type 2 diabetes in high-risk individuals.

To prevent diabetes, focus on eating more fruits, vegetables, and whole grains, and stay active. You do not need to eliminate carbohydrates; in fact, a balanced diet with moderate carbs is safer and just as effective for long-term health.

Increasing leisure-time physical activity (LTPA) in later adulthood (ages 40-61) after a period of inactivity reduces all-cause, cardiovascular disease (CVD), and cancer-related mortality to levels comparable to those who maintain high activity levels from adolescence.

If you have been inactive for most of your life, starting or significantly increasing your physical activity between ages 40 and 61 can drastically lower your risk of dying from any cause, heart disease, or cancer. You do not need to have been an athlete since youth to gain these life-extending benefits; the key is to become active in later adulthood.

Simple step-count monitoring interventions (pedometers) significantly increase daily step counts in community-dwelling adults, with effects sustained for up to 3-4 years, whereas more complex interventions (body-worn trackers, smartphone apps, counseling, or incentives) do not provide additional benefit and may be less effective.

Use a simple pedometer. It works. You don't need a smartphone app, a body-worn tracker, or expensive counseling to increase your steps. The data shows that simple step-count monitoring leads to sustained increases in physical activity for years, while more complex interventions offer no extra benefit and may even be less effective.

Lifestyle modification (diet and exercise) is the first-line therapy for dyslipidemia in PCOS, and statins are a novel therapeutic approach that improves lipid profiles and reduces testosterone and insulin resistance.

Start with diet and exercise as your primary treatment for PCOS-related lipid issues. If your LDL remains high (above 160 mg/dL) or non-HDL-C is high (above 190 mg/dL) despite lifestyle changes, discuss statins with your doctor. Statins can help lower both cholesterol and testosterone/insulin resistance, but you must use contraception if taking them.

Functional and balance training performed at least twice weekly significantly reduces the rate of falls in adults over 50, with high-certainty evidence supporting this intervention for fracture prevention.

Perform balance and functional exercises at least twice a week. Focus on activities that challenge your stability, such as standing on one foot, heel raises, or agility drills. Progressively make these exercises harder by increasing speed, complexity, or resistance. This is the most effective non-pharmacological way to prevent falls in older adults.

Aerobic exercise training significantly reduces HbA1c levels in individuals with type II diabetes, with the magnitude of reduction increasing as program duration extends beyond 12 weeks.

Engage in aerobic exercise regularly. While any amount helps, extending your program duration beyond 12 weeks is key to maximizing HbA1c reductions. Aim for a median of 150 minutes per week, spread over 3 sessions, to see significant clinical improvements in blood sugar control.

Resistance training combined with amino acid supplementation is the most effective current strategy to prevent age-related muscle wasting and weakness.

To prevent muscle loss as you age, the best approach is to engage in resistance training and ensure you are getting enough amino acids (protein) in your diet. This is more effective and safer than pharmaceutical interventions.

Higher levels of leisure-time physical activity are consistently and positively associated with higher cardiorespiratory fitness (CRF) in adults.

To improve your cardiorespiratory fitness, prioritize your leisure-time physical activity. This doesn't necessarily mean joining a gym; it includes any recreational exercise you do. The evidence shows that doing more of this activity consistently leads to better fitness levels, which is a strong predictor of long-term health.

Group-based education excluding patients on insulin therapy results in greater reductions in HbA1c compared to interventions including patients on insulin therapy.

If you are on insulin, group education still helps, but the HbA1c reduction might be smaller than for those not on insulin. This may be due to the complexity of balancing insulin with lifestyle changes.

Lifestyle interventions (caloric restriction and exercise) are the foundation of MASLD treatment but often fail to achieve sufficient or sustained weight loss, necessitating pharmaceutical intervention.

Start with lifestyle changes: eat less and move more. This is the foundation of treating fatty liver. However, be realistic: it is very hard to maintain these changes long-term, and many people struggle to lose enough weight. If lifestyle changes are not enough, talk to your doctor about adding medications like GLP-1RAs or SGLT2-is, which can help you achieve the weight loss needed to improve your liver health.

Current clinical guidelines recommend continuing GLP-1 receptor agonists for most patients undergoing elective surgery, shifting away from routine preoperative cessation.

Do not stop your GLP-1 medication before surgery unless your surgeon or anesthesiologist explicitly tells you to. Most modern guidelines now say you should keep taking it, and you should discuss your specific risk factors with them.

Using multiple 24-hour recalls (averaging 2-3) significantly improves the correlation with true intake compared to a single recall, but still yields low attenuation factors for energy and protein.

If you must use self-report, do not rely on a single day. Use 2-3 days of recalls to improve accuracy, but understand that the correlation with true intake remains low (0.31 for energy). For precise absolute intake, use biomarkers.

Higher Body Mass Index (BMI) is a strong predictor of increased under-reporting of energy and protein intake in both FFQs and 24-hour recalls.

If you have a higher BMI, your self-reported food intake is likely to be significantly underestimated. Use calibration equations that include your BMI to get a more accurate estimate of your true intake.

The IWQOL-Lite-CT is a validated patient-reported outcome measure that accurately detects clinically meaningful improvements in physical and psychosocial functioning in patients with overweight or obesity undergoing weight management interventions.

Use the IWQOL-Lite-CT to track how weight loss interventions impact patients' daily physical and psychosocial functioning. It is a validated, 20-item questionnaire that provides a comprehensive assessment of treatment benefit from the patient's perspective, suitable for clinical trials and potentially clinical practice to gauge meaningful within-patient change.

Behavioral weight management programs (BWMPs) involving diet and/or exercise do not harm mental health despite common weight regain, and may improve specific mental health dimensions (psychological wellbeing, self-esteem, depression, anxiety) at and after program end.

If you are doing a weight loss program, don't worry if you regain some weight; it doesn't mean your mental health will suffer. In fact, these programs often improve your self-esteem, anxiety, and overall wellbeing, even after the program ends. Focus on the behavioral changes and mental health benefits, not just the scale.

Resistance exercise studies must report specific training parameters (e.g., exercise selection, intensity, volume, rest intervals) to ensure scientific transparency and allow for replication.

If you are designing or reporting a resistance training study, use the PRIRES checklist to ensure you report all relevant training parameters, including exercise selection, intensity, volume, rest intervals, and progression rules.