Health & Fitness
Activity Multipliers: How to Pick the Right One for Your TDEE
The activity factor you choose changes your calorie estimate far more than the BMR equation does. Here is what each level means and how to avoid the usual overestimate.
Health & Fitness
Guides to body measurements, calories, sleep and training numbers, with worked examples and what each figure does and does not tell you.
Health & Fitness
BMI for Children and Teens: Why Percentiles Replace Cutoffs
A child's BMI is calculated like an adult's, but it is judged against other children of the same age and sex. Here is how percentiles work and what the bands mean.
Health & Fitness
Mifflin-St Jeor vs Harris-Benedict vs Katch-McArdle for BMR
Different BMR equations give different answers for the same person. Compare Mifflin-St Jeor, Harris-Benedict and Katch-McArdle on one set of numbers and see why they differ.
Health & Fitness
Calorie Deficit Math: Setting a Target and Estimating a Timeline
A daily calorie deficit converts into a predicted rate of weight loss with simple division. Here is the arithmetic, why the plan slows down over time, and where the limits are.
Health & Fitness
Healthy Weight Range for Your Height: How It Is Calculated
A healthy weight range is a BMI band turned back into kilograms. Here is the arithmetic, a table for common heights, and why a range beats a single ideal number.
Health & Fitness
Heart Rate Zones: Percent of Max vs Heart Rate Reserve
Heart rate zones turn "how hard am I working?" into numbers. Learn the two common ways to calculate them and why the same percentage can mean two different heart rates.
Health & Fitness
How to Calculate BMI by Hand in Metric and Imperial Units
BMI is one division and one squared number. Here is the metric and imperial method, the common unit slips, and how to run the formula backwards to find a target weight.
Health & Fitness
How to Estimate Body Fat With a Tape Measure (US Navy Method)
A soft tape and a log button are enough to estimate body fat. Here is the US Navy method step by step, what the percentage means, and how far to trust it.
Health & Fitness
Sleep Cycles and Bedtimes: Working Out When to Sleep
Count back from your wake-up time in blocks of about 90 minutes to find a sensible bedtime. Here is the arithmetic, a quick-reference table and what the method cannot promise.
Health & Fitness
What BMI Can and Cannot Tell You About Your Health
Two people can share the same BMI and have very different bodies. Here is what the number was designed for, where it falls short, and what to pair it with.