Browse the evidence

Caffeine consumption in volleyball players yields mixed results, with some studies showing improved jump height and ball velocity, while others show no performance enhancement.

Caffeine may help your jump and serve speed, but it doesn't work for everyone. If you try it, use a moderate dose (3mg/kg) before competition and test it in practice first to ensure it doesn't cause anxiety or jitters.

Moderate-to-high intensity physical activity improves lipid profiles (reducing LDL, Triglycerides, and Total Cholesterol while increasing HDL) in patients with Coronary Artery Disease (CAD).

If you have coronary artery disease and your doctor clears you for exercise, engaging in moderate-to-high intensity physical activity (like brisk walking, cycling, or interval training) for 30 minutes, 3-5 times a week, can significantly improve your cholesterol levels by lowering bad cholesterol (LDL) and triglycerides while raising good cholesterol (HDL). High-intensity interval training (HIIT) may offer greater lipid benefits than moderate continuous training, but always consult your cardiologist before starting.

Higher adherence to the PURE diet score is significantly associated with lower odds of depression and anxiety in adults at high cardiovascular risk, with the association being statistically significant in women but not in men.

Focus on adding fruits, vegetables, legumes, nuts, fish, and whole-fat dairy to your daily diet. This pattern, known as the PURE diet, is linked to lower risks of depression and anxiety, especially in women. You do not need to strictly eliminate animal products or dairy to see benefits; the key is overall dietary quality and nutrient density rather than extreme restriction.

Virtual weight care programs prescribing a broad range of antiobesity medications alongside behavior change achieve clinically significant weight loss (mean 8.0% at 12 months) in real-world settings, with higher engagement correlating with greater weight loss.

Engage with a structured virtual weight care program that combines medication with behavioral support. Higher engagement with the program (logging weight weekly, interacting with coaches) correlates with greater weight loss (up to 12%). You do not need the most expensive medications to achieve significant results; a broad range of medications, when paired with consistent engagement, can lead to clinically meaningful weight loss.

Resistance training load (intensity) does not significantly impact skeletal muscle hypertrophy, provided sets are performed to or near volitional fatigue.

You do not need to lift heavy weights to build muscle. Whether you use light weights for many reps or heavy weights for few reps, muscle growth is similar as long as you work close to failure. This allows you to choose loads that feel good for your joints.

Highly processed foods containing 'acellular' nutrients (refined starches/sugars lacking cellular structure) promote obesity by altering gut microbiome composition, increasing host nutrient absorption, and reducing microbiome energy use.

Choose whole, minimally processed foods over refined, 'acellular' carbohydrates (like white flour or sugar). The intact cellular structure of whole foods feeds your gut microbiome, which helps regulate how much energy you extract and store.

In patients with inflammatory bowel disease (IBD) and obesity, weight loss therapy should prioritize selective fat mass reduction while preserving lean body mass (muscle) to avoid worsening sarcopenia and surgical risk.

If you have IBD and are overweight, your weight loss goal is different from the general population. You must prioritize keeping your muscle mass. Standard diets that just cut calories might hurt your muscles. You need a plan that specifically protects lean body mass, likely involving higher protein intake and monitoring muscle function, not just the scale number.

High consumption of ultra-processed foods (UPFs) is associated with specific alterations in gut microbiota composition, including decreased Lachnospira and Ruminococcus species and increased Prevotella species, though effects on overall microbial diversity (alpha/beta) are inconsistent across studies.

If you consume a high amount of ultra-processed foods, you may see a shift in your gut bacteria, specifically a decrease in beneficial fiber-fermenting types like Lachnospira and an increase in Prevotella. While overall diversity might not change significantly in all cases, these specific shifts are linked to higher UPF intake. To support a healthier microbiome, consider reducing UPF intake and increasing fiber-rich whole foods.

High consumption of ultra-processed foods is associated with negative health outcomes including increased depression/anxiety, higher BMI/weight, and decreased HDL cholesterol, particularly in men consuming >5 servings/day.

Eating more than 5 servings of ultra-processed foods daily is linked to higher body weight, worse cholesterol (lower HDL in men), and higher rates of depression and anxiety in women. Reducing UPF intake below this threshold may help improve these health markers.

Switching from continuous full-dose GLP-1/IM therapy to a lower-cost, less effective alternative weight-maintenance program after reaching a weight-loss plateau generates substantial lifetime healthcare savings with only minimal reductions in quality-adjusted life years (QALYs).

If you have successfully lost weight using GLP-1 medications (like Wegovy or Ozempic) and your weight has stabilized, discuss with your doctor whether switching to a lower-cost maintenance strategy (such as a lower dose, a different medication, or a focus on lifestyle/nutrition support) is appropriate for you. This approach may save you significant money and reduce side effects while maintaining a substantial portion of your health benefits, with the option to return to full-dose therapy if you regain weight.

Pre-contest preparation in physique athletes involves significant caloric restriction and high-volume training, leading to marked alterations in body composition, hormonal profiles, and psychometric outcomes, with sex-specific divergent responses in lean mass and hormone regulation.

If you are preparing for a physique competition, expect significant changes. You will likely lose 8-9% body fat over 3-8 months. Men may lose lean mass despite high protein intake, while women may maintain or slightly gain it. Hormones like testosterone will drop in men, and cortisol will rise in both sexes. Sleep quality and mood may suffer. This is a controlled stressor; manage it with consistent resistance training and gradual caloric deficits.

Highly effective anti-obesity medications (heAOMs) achieving 15% or more weight reduction can cause 'excessive weight reduction' leading to psychosocial challenges, nutrient deficiencies, and lean body mass loss, requiring proactive management including body composition analysis and behavioral support.

If you are taking a powerful weight loss medication and losing weight rapidly (15% or more), you need to monitor more than just your weight. Ask your doctor for a body composition analysis to ensure you aren't losing too much muscle or essential fat. Prioritize protein intake and resistance training to protect your muscle. Be prepared for changes in your social relationships and mental health, and seek support if you feel isolated or if friends/family react negatively to your changes.

Consuming chickpeas significantly reduces postprandial blood glucose (iAUC) compared to wheat, potatoes, pasta, cheese, rice, and corn in healthy or normoglycemic adults.

Replace high-glycemic sides like white rice, potatoes, or pasta with chickpeas (whole, flour, or puree) to significantly blunt blood sugar spikes. This works best if you are not diabetic, but the mechanism (resistant starch/fiber) benefits everyone. Note that insulin response benefits are less consistent than glucose benefits.

A 6-month intensive, multidisciplinary lifestyle intervention significantly reduces 24-hour systolic and diastolic blood pressure in patients with resistant hypertension.

If you have resistant hypertension, standard advice to 'just exercise and eat better' often fails because the condition is complex. This study shows that a structured, supervised program involving diet, exercise, and sleep management can significantly lower blood pressure. Success requires commitment to regular visits and personalized guidance from a healthcare team.

HMB supplementation alone (3g/day) prevents the decline in muscle mass and grip strength in elderly sarcopenic patients after hip surgery, but does not significantly increase muscle mass or strength compared to baseline.

Take 3g of HMB daily after hip surgery. It won't build new muscle on its own, but it may help stop your muscles from shrinking as much as they otherwise would during recovery.

Adherence to the Mediterranean Diet (MED) or Dietary Approaches to Stop Hypertension (DASH) improves cardiovascular disease risk biomarkers (total and LDL cholesterol, blood pressure) and reduces oxidative stress and inflammation in postmenopausal women.

Focus on whole-food dietary patterns like the Mediterranean or DASH diet, emphasizing fruits, vegetables, whole grains, and healthy fats. These patterns have been shown to improve cholesterol and blood pressure in postmenopausal women, addressing key cardiovascular risks associated with hormonal changes.

GLP-1 receptor agonists and dual GIP/GLP-1 agonists cause unintended nutritional complications, including severe caloric restriction (<800 kcal/day), lean body mass loss (approx. 25-45% of total weight loss), micronutrient deficiencies, dehydration, and rare ketoacidosis, necessitating structured dietitian-led monitoring.

If you are taking GLP-1 medications like semaglutide or tirzepatide, do not rely on appetite alone to guide your diet. You are at risk of losing muscle and missing essential nutrients. Aim for at least 1200-1500 kcal/day and 1-1.4 grams of protein per kilogram of body weight daily. Prioritize nutrient-dense foods and stay hydrated. Work with a dietitian to monitor your intake and adjust your plan to prevent fatigue, dizziness, or muscle loss.

Consumption of protein supplements by muscle builders significantly alters gut microbiome composition and fecal metabolome, specifically increasing the abundance of Lactobacillales and allantoin while decreasing nucleotide metabolism gene expression compared to non-supplement users.

If you use protein supplements, your gut bacteria and metabolites will look different than non-users, specifically with higher levels of Lactobacillales and allantoin. This is a normal adaptation to higher protein/purine intake and does not imply negative health effects in this population.

High adherence to a Mediterranean diet improves inflammatory biomarkers (triglycerides, hsCRP) in individuals with the TNF rs1800629 GG genotype, demonstrating that dietary patterns can modulate genetic inflammation risk.

If you have the TNF rs1800629 GG genotype, you are genetically predisposed to higher inflammation and triglycerides. Adopting a Mediterranean diet for at least one year can significantly improve these markers, reducing your cardiovascular risk. This is a key example of how diet can counteract genetic inflammation.

Probiotic supplementation has a regulatory effect on weight and BMI, with greater weight loss magnitude observed in populations with longer treatment durations.

If you are considering probiotics for weight management, look for strains with clinical evidence for obesity. The paper notes that longer treatment durations are associated with greater weight loss, suggesting consistency is key. It is not a quick fix but may support metabolic health over time.

Lifestyle interventions (diet and exercise) significantly improve sperm normal morphology and progressive motility in men with obesity, whereas bariatric surgery and pharmacotherapy (metformin/liraglutide) show no clinically significant improvements in semen parameters or DNA damage.

If you are overweight and trying to conceive, focus on sustainable lifestyle changes (diet and exercise) rather than seeking surgical or pharmacological weight loss solutions solely for fertility. Lifestyle changes have been shown to improve sperm morphology and motility, whereas surgery and weight-loss drugs have not shown consistent benefits for semen quality in this population.

N-of-1 study designs provide a higher level of evidence for determining individualized treatment efficacy in medical nutrition therapy compared to traditional Randomized Controlled Trials (RCTs), which often mask individual variance through mean effect sizes.

If you are a dietitian, standard RCT-based guidelines may not work for every patient because individual responses vary widely. To practice true precision nutrition, consider using N-of-1 trial designs (testing one patient against themselves with multiple diet phases) to identify the specific dietary pattern that works for that individual's biology and lifestyle, rather than relying solely on population averages.

Combining tirzepatide with low-energy ketogenic therapy (LEKT) produces significantly greater reductions in hepatic steatosis and liver stiffness than combining tirzepatide with a low-calorie diet (LCD), independent of total body weight loss.

If you have MASLD and are using tirzepatide, adding a structured low-energy ketogenic diet (under 30g carbs, ~1200 kcal) for 12 weeks may reduce liver fat and stiffness more effectively than a standard low-calorie diet, even if your total weight loss is similar. This requires strict adherence and monitoring, ideally under medical supervision, to ensure safety and efficacy.

High-calorie, high-protein nutritional supplementation and specific supplements (L-alanyl-L-glutamine + PUFAs) can counteract lean mass loss and improve quality of life in heart failure patients, potentially mitigating GLP-1RA-induced sarcopenia.

If you are losing muscle on heart failure medication, ask your doctor about high-protein nutritional supplements. Specific combinations like glutamine and fish oil (PUFAs) have been shown to help increase lean body mass and improve how you feel.