Browse the evidence

In breast cancer patients, higher intake of animal and plant proteins correlates significantly with greater muscle mass, whereas total energy intake does not.

If you are a breast cancer patient, focus on getting enough protein (both animal and plant sources) rather than just counting calories. Your muscle mass is linked to how much protein you eat, not just how many calories. Don't avoid meat or dairy out of fear; ensure you are getting adequate protein to protect your muscles.

Professional indoor and beach volleyball players consistently fail to meet recommended carbohydrate intake levels, averaging 4.01 g/kg/day against a recommended 5-10 g/kg/day.

If you play competitive volleyball, your current carb intake is likely too low for optimal performance. Aim to increase carbohydrates to at least 5 grams per kilogram of body weight daily, especially on training days, to support your energy demands.

High intake of refined carbohydrates is associated with increased dietary risk for metabolic syndrome, with 50% of the studied judicial officers exhibiting this habit.

Half of the judicial officers in this study ate high amounts of refined carbohydrates, which drives obesity and insulin resistance. If you consume a lot of white bread, rice, or sugary foods, reducing these refined carbs is a key step in preventing metabolic syndrome, alongside increasing physical activity.

Consumption of specific edible oils (frying, sunflower, olive) with fatty acid profiles within standard ranges is associated with a reduction in household oil intake, which may help reduce the risk of chronic diseases.

To support heart health, consider reducing your overall intake of cooking oils, particularly frying, sunflower, and olive oils, which are commonly consumed. Ensure the brands you choose have fatty acid profiles that meet national standards, as some brands may have non-compliant levels of saturated or specific fatty acids. Reading labels can help you make informed choices, although many consumers find this difficult.

Polyglucosamine supplementation (800-1700 mg/day) combined with caloric restriction and physical activity produces a statistically significant, albeit modest, reduction in body weight (-1.78 kg) and BMI (-1.52 kg/m2) compared to lifestyle interventions alone in overweight and obese adults.

If you are overweight, taking polyglucosamine (approx 1-1.7g daily, split into doses with meals) alongside a calorie-restricted diet and moderate exercise will help you lose slightly more weight (about 1.8 kg more) than diet and exercise alone over 3-12 months. It is not a magic solution, but a small booster.

Low-carbohydrate diets (5-25% energy from carbohydrate) improve cardiometabolic markers (weight, HDL, triglycerides) in healthy adults over 12 weeks, with greater carbohydrate restriction yielding larger improvements in HDL and triglycerides.

Adopting a low-carbohydrate diet (5-25% of calories from carbs) for 12 weeks can improve your weight, waist size, and key blood markers like HDL and triglycerides, even if you don't change your total calorie intake. While stricter diets (5% carbs) yield the best blood marker improvements, moderate restriction (15-25% carbs) is easier to stick to and still provides significant health benefits.

High intake of total trans fatty acids, particularly industrially produced trans fats, is associated with increased risk of all-cause mortality, coronary heart disease (CHD) mortality, and total CHD.

Avoid industrially produced trans fats (found in partially hydrogenated oils) as they increase the risk of heart disease and death. Ruminant trans fats (from natural sources like dairy and meat) do not show the same harmful effects and may even have some benefits. Focus on avoiding industrial trans fats rather than demonizing all fats.

Replacing dietary carbohydrates with saturated fats reduces the risk of stroke and all-cause mortality, whereas replacing carbohydrates with unsaturated fats or animal-derived proteins increases mortality risk.

If you are currently eating a high-carbohydrate diet, consider replacing some of those refined carbs with plant-based fats (like those from nuts or seeds) rather than animal fats. This substitution has been linked to a lower risk of stroke and mortality in large population studies, challenging the old advice to simply cut all fat.

Eating three to six meals per day with 0.4-0.5 g/kg of protein in meals surrounding resistance training likely maximizes theoretical benefits of nutrient timing, but alterations in timing and frequency have little effect on fat loss or lean mass retention.

Aim for 3-6 meals per day, ensuring each meal contains 0.4-0.5 g/kg of your body weight in protein. Try to have a protein-rich meal before and after your training sessions. However, do not stress if you cannot hit these times perfectly; your total daily protein intake is much more important for your results.

Long-chain saturated fatty acids (LCSFA, C12-C18) are associated with an increased risk of cardiovascular disease (CVD), whereas short- and medium-chain fatty acids (SCFA/MCFA, C4-C10) are associated with neutral or potentially beneficial effects on CVD risk.

When evaluating saturated fats, distinguish between long-chain (found in meat and cheese) and short/medium-chain (found in dairy fats, coconut oil). Current evidence suggests long-chain fats may increase CVD risk, while short and medium-chain fats may be neutral or beneficial. Focus on the source and type of fat rather than avoiding all saturated fats indiscriminately.

Replacing saturated fatty acids with refined carbohydrates or animal protein increases CVD risk, whereas replacing them with unsaturated fats, plant protein, or complex carbohydrates reduces or has a neutral impact on CVD risk.

If you reduce saturated fat, ensure you replace it with unsaturated fats (like olive oil or nuts), plant proteins (beans, lentils), or complex carbohydrates (whole grains). Avoid replacing saturated fat with refined carbohydrates (sugar, white flour) or animal proteins, as these substitutions may increase cardiovascular risk.

Conjugated linoleic acid (CLA) supplementation slightly reduces body fat mass and increases lean body mass in people with overweight and obesity, but may have adverse effects on glucose metabolism and inflammation.

CLA supplementation can lead to small reductions in fat mass and increases in lean mass, but it also carries risks of worsening glucose metabolism and lowering HDL cholesterol. It is not recommended as a primary strategy for body composition improvement compared to dietary fat quality adjustments.

Fat intake should be maintained at 10-25% of total calories during contest preparation to allow for adequate carbohydrate intake for performance, avoiding very low fat for long periods.

Set your fat intake to 10-25% of your daily calories. Do not drop it lower for extended periods. Prioritize getting your protein (1.8-2.7 g/kg) and carbohydrates (2-5 g/kg) first, then fill the remaining calories with fat. This ensures you have enough energy for training and supports hormonal health.

For adults with marginal or inadequate protein intake (<0.8 g/kg/day), consuming a more balanced protein distribution (spreading protein across meals) is superior to an unbalanced distribution for promoting skeletal muscle-related outcomes.

If you are currently eating less than 0.8 grams of protein per kilogram of body weight per day, try spreading your protein out more evenly across your meals. This helps your body use the protein it has more efficiently. However, if you are already eating a healthy amount of protein (0.8-1.3 g/kg), you don't need to stress about balancing every meal; just make sure at least one meal has enough protein (around 25-30g) to trigger muscle building.

For adults with adequate or high protein intake (0.8-1.3 g/kg/day), ensuring at least one meal contains sufficient protein to maximally stimulate muscle protein synthesis is sufficient for promoting skeletal muscle health, regardless of how the rest of the day's protein is distributed.

If you are already eating enough protein each day (around 0.8 to 1.3 grams per kilogram of body weight), you don't need to worry about spreading it out perfectly. Just make sure one meal a day has enough protein (about 25-30 grams) to trigger muscle building. The rest of your protein can be distributed however fits your schedule.

Specific genetic variants (e.g., FTO, TCF7L2, FABP2) modify the body's response to macronutrient intake, such that high-protein or specific fat/carbohydrate ratios yield different weight loss or metabolic outcomes depending on the individual's genotype.

If you have known genetic risks (like FTO variants), standard high-carb or low-fat diets might not be optimal. Consider discussing with a professional whether a high-protein or specific fat-modified diet aligns with your genetic profile for better weight management.

High intake of dietary fiber, particularly soluble and cereal fiber, improves glycemic control, reduces HbA1c, and lowers the risk of type 2 diabetes.

Increase your daily intake of dietary fiber by eating more fruits, vegetables, legumes, nuts, and whole grains. This can significantly improve blood sugar control, lower HbA1c, and reduce the risk of type 2 diabetes.

Adherence to a Mediterranean diet is associated with lower risk of type 2 diabetes in white populations, but this association is not consistently observed in non-white ethnic groups (Native Hawaiians, Japanese Americans) when using standard MedDiet scores.

While the Mediterranean diet is beneficial for preventing type 2 diabetes in white populations, its effectiveness may vary in other ethnic groups. For Native Hawaiians and Japanese Americans, other dietary patterns (like DASH or alternate Healthy Eating Index) might be more predictive of diabetes risk. Focus on overall diet quality and culturally appropriate healthy foods rather than strict adherence to a specific named diet.

In pre-frail and frail older adults, a 6-month multi-component exercise program combined with twice-daily protein supplementation (20g per dose) improves grip strength and physical performance regardless of whether the protein source is whey or rice, indicating that total protein quantity and exercise adherence are more critical than protein quality (amino acid profile).

If you are an older adult at risk of frailty, focus on doing regular multi-component exercise (strength, balance, walking) and ensuring you get enough protein (around 40g/day from supplements if needed) rather than stressing about whether the protein is whey or rice. Both work for improving strength and physical performance. If whey causes stomach upset, try rice protein instead.

High protein intake (1.7–2.3 g/kg/day) improves lean body mass retention during low-energy diets, but evidence for its benefit during very-low-energy diets (VLEDs) is conflicting.

Eat more protein (around 1.7-2.3g per kg of body weight) if you are on a low-calorie diet to help keep your muscle. However, if you are on a very strict very-low-calorie diet, extra protein might not help as much as you hope, and results vary. Check with your doctor if you have kidney issues.

Whey protein supplementation (concentrated, hydrolyzed, or isolated) significantly reduces fat mass compared to isocaloric carbohydrate placebos in healthy adults undergoing resistance training, but does not significantly increase fat-free mass.

If you are doing resistance training, switching from a carbohydrate-based post-workout drink to whey protein may help you lose a small amount of fat mass over ~2 months. Do not expect this to build muscle mass; the study found no significant difference in fat-free mass gains between whey and placebo groups.

High-fat diets (specifically ketogenic diets with >75% fat) increase total and free testosterone in resistance-trained men compared to Western diets, likely due to higher cholesterol intake supporting steroidogenesis.

If you are resistance training, ensure you consume enough dietary fat (at least 25% of calories). Very low-fat diets may suppress testosterone. Some evidence suggests ketogenic diets (high fat, very low carb) may further boost testosterone in trained men, likely due to cholesterol availability for hormone synthesis.

Soy protein supplementation may blunt the acute post-exercise testosterone response compared to whey protein or placebo, although it does not necessarily lower resting total testosterone.

Soy protein is safe and does not lower your baseline testosterone. However, if you want to maximize the acute testosterone spike after heavy lifting, whey protein might be a slightly better choice than soy. For general health and muscle building, either is fine.

High dietary cholesterol intake (≥538 mg/day) is associated with a significantly increased risk of high total cholesterol and high LDL-C in Chinese metropolitan adults, particularly women.

For Chinese metropolitan adults, consuming more than 538 mg of dietary cholesterol daily is linked to higher risks of high total cholesterol and LDL-C, especially for women. While current guidelines may not enforce a strict limit, monitoring intake to stay below this threshold may be prudent for lipid management.