Guides
Deep dives on the science behind every calculator — how the formulas work, where they break down, and how to apply the numbers to real training and nutrition.
Nutrition & Energy
Understanding Activity Multipliers (and Why Most People Pick Wrong)The activity multiplier turns your resting metabolism into daily calories — and it's where nearly all calorie-estimate errors come from. Here's how to choose honestly.Taylor Brooks · 6 min readHow to Self-Calibrate Your TDEE from Real DataFormula estimates get you close; your own kitchen scale and bathroom scale get you exact. A two-to-three-week protocol to find your true maintenance calories.Alex Carter · 6 min readProtein and Muscle Preservation During GLP-1 Weight LossGLP-1 medications drive rapid weight loss and blunt appetite — which makes protecting muscle harder. Here's the nutrition-and-training framing, minus any medical advice.Alex Carter · 6 min readWhy Mifflin-St Jeor Beats Harris-Benedict for Estimating MetabolismTwo equations estimate your resting metabolism from the same inputs — yet one is meaningfully more accurate for modern bodies. Here's why, and when to use each.Taylor Brooks · 6 min readThe Complete Guide to Calorie and Macro TrackingHow to find your maintenance calories, set a sane deficit or surplus, and split the total into protein, fat, and carbs you can actually hit.Alex Carter · 6 min read
Body Composition
BMI vs Body Fat vs Waist-to-Height: Which Metric Wins?Three ways to measure whether your body is in a healthy place. We compare cost, accuracy, and what each one actually predicts — and how to combine them.Taylor Brooks · 6 min readWhy BMI Misclassifies Athletes (and What to Use Instead)BMI routinely labels muscular people 'overweight' and lean-but-unfit people 'healthy.' Here's the math behind the error and the metrics that fix it.Dr. Sam Rivera · 6 min readThe Complete Guide to Body CompositionWhat body composition really measures, how BMI, body fat, and healthy-weight ranges fit together, and which numbers actually predict health.Dr. Sam Rivera · 6 min read
Strength
Strength Training After 60: A Practical, Evidence-Based GuideMuscle and strength decline with age — but resistance training reverses much of it at any age. How to start safely, progress sensibly, and eat to support it.Jordan Hale · 6 min readEpley vs Brzycki vs Lombardi: Comparing the 1RM FormulasA head-to-head look at the three most common one-rep-max formulas — how each behaves across rep ranges, where they diverge, and which to standardize on.Jordan Hale · 6 min readWhy 1RM Formulas Disagree — and Which Number to TrustFeed the same set into three one-rep-max formulas and get three different maxes. Here's why they diverge, where each is most accurate, and how to pick.Jordan Hale · 6 min readThe Complete Guide to Strength Standards and Your One-Rep MaxWhat a one-rep max really is, how to estimate it safely, how to read strength standards without ego, and how to turn the number into a training plan.Jordan Hale · 6 min read
Endurance & Activity
What Your Watch's VO2 Max Actually MeasuresYour smartwatch reports a VO2 max number, but it never measured your oxygen uptake. Here's what it's really estimating, how accurate it is, and how to use it.Dr. Sam Rivera · 6 min readCardio vs Weights for Fat Loss: What the Evidence SaysShould you run or lift to lose fat? We compare calorie burn, muscle retention, appetite, and time efficiency — and land on what actually works.Taylor Brooks · 6 min readThe Complete Guide to Endurance Training MetricsHeart-rate zones, VO2 max, pace, calories burned, and hydration — the endurance numbers that matter and how to use them without drowning in data.Dr. Sam Rivera · 6 min read