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Evidence-based guides on fitness, nutrition, and understanding health metrics.
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The Relative Age Effect: Why Birth Month Shapes School and Sport
Ketogenic Diets and Nutritional Ketosis: What the Research Shows About Weight Loss, Performance, and Who Should Be Cautious
Ketogenic diets shift the body's fuel source from glucose to fat and ketones — a measurable metabolic state with the strongest evidence base in drug-resistant epilepsy. Here's how nutritional ketosis differs from dangerous diabetic ketoacidosis, what weight loss research actually shows over longer timeframes, and the mixed evidence on athletic performance.
Harris-Benedict vs Mifflin-St Jeor vs Katch-McArdle: Why BMR Formulas Disagree by 100-200 Calories
BMR calculators don't all use the same formula — Harris-Benedict (1919, revised 1984), Mifflin-St Jeor (1990), and Katch-McArdle (lean-mass-based) can disagree by 100-200 calories for the same person, which represents 20-30% of a typical weight-loss deficit. Here's how each formula was developed, why they diverge more for people at the extremes of body composition, and why any formula's output should be treated as a starting point rather than a precise target.
BMI and Pregnancy: Why Pre-Pregnancy BMI Matters and "Current BMI" During Pregnancy Doesn't Mean What You'd Think
A pregnant person's BMI increases throughout pregnancy simply because of the pregnancy itself — applying standard BMI categories to this changing number would be meaningless. Here's why clinical weight-gain guidance uses pre-pregnancy BMI as a fixed reference point instead, why "total weight gain from that reference point" is the relevant question rather than "current BMI category," and how postpartum BMI takes time to become meaningful again.
BMI and Ethnicity: Why the WHO Recommends Lower Thresholds for Asian Populations
A BMI of 24 is "normal" by standard categories but already represents "increased risk" under WHO's Asian-specific BMI cut-offs (23 for overweight, 27.5 for obese). Here's why these adjustments exist, the body composition research behind them, UK NICE guidance for multiple ethnic groups, and why waist circumference complements BMI across populations.
EPOC, the "Afterburn Effect," and HIIT vs Steady-State: Separating Research from Marketing
EPOC ("afterburn") adds approximately 6-15% to a workout's calorie burn — real, but smaller than fitness marketing implies. Here's what EPOC actually measures, why HIIT's real advantage is time efficiency rather than metabolic magic, how HIIT and steady-state compare for fat loss, and how resistance training's EPOC differs from cardio's.
Intermittent Fasting and Meal Timing: Does When You Eat Actually Matter?
Intermittent fasting's weight loss effect appears to come largely from spontaneous calorie reduction, not a separate metabolic pathway — but circadian research suggests eating earlier in the day may benefit glucose tolerance independent of weight. Here's what controlled trials actually show about meal timing, autophagy claims in context, and who IF tends to suit.
Twin Pregnancy Due Dates, Chorionicity, and IVF Dating: How Multiple Pregnancies Differ
Twin pregnancies average 36-37 weeks rather than 40 — meaning a standard due date calculation represents a date most twin pregnancies won't reach. Here's why multiples arrive earlier, how chorionicity affects monitoring and timing, why IVF dating from embryo transfer is the most precise method available, and what vanishing twin syndrome means for dating.
Why Ideal Weight Formulas Break Down for Athletes and Anyone With Above-Average Muscle Mass
A bodybuilder at 95kg with 8% body fat and a sedentary man at 95kg with 30% body fat get an identical "ideal weight" from every classic formula — because none of them account for muscle mass. Here's why NFL linemen and Olympic weightlifters routinely fall into "obese" categories by BMI and ideal weight formulas, and what's actually useful for athletic populations instead.
Child Growth Charts: How Percentiles Work, Predicting Adult Height, and Growth Spurt Timing
A single growth chart percentile tells you how a child compares to peers at one moment — but tracking the trend over time, particularly whether a child crosses percentile lines, is what growth monitoring is really designed to reveal. Here's how growth charts work, the mid-parental height formula for estimating adult height, and how growth spurts differ between boys and girls.
Age in Different Cultures and Legal Systems: Korean Reckoning, Age of Majority, and Leap Year Birthdays
South Korea officially ended traditional age reckoning in 2023, where everyone ages on New Year's Day making you 1-2 years "older" than by Western count. The US drinking age of 21 is unusual globally; Germany allows beer at 16; Scotland sets adulthood at 16 for contracts. Here's how age is defined differently around the world.
Chronotypes and Circadian Rhythms: Why Night Owls Can't Just Choose to Be Morning People
Night owls aren't lazy — chronotype is 50–60% heritable and adolescent biology genuinely delays sleep timing. Here's how circadian rhythms work, the measurable health costs of social jetlag, why school start times are a public health issue, and how light exposure can shift (but not transform) chronotype.
Walking Pace and Longevity: Why How Fast You Walk Predicts Health Better Than Step Count
Brisk walkers have 35% lower all-cause mortality and 54% lower cardiovascular mortality than slow walkers — independently of total walking volume. Here's what "brisk" means in measurable terms, the dose-response curve from pace improvements, and why gait speed predicts health in ways step count doesn't.
