Guides
Health & Fitness Guides
Clear, practical answers to the questions behind the numbers — each one paired with the free calculator that puts it to work.
How Many Calories Should You Eat to Lose Weight? Find your maintenance calories, set a safe deficit, and turn it into a daily target. Read the guide → How Much Water Should You Drink a Day? The real answer beyond '8 glasses' — how much fluid you actually need and why. Read the guide → What Is a Healthy BMI? Chart, Ranges and Limits The healthy BMI range, the full category chart, and where BMI falls short. Read the guide → How to Count Macros for Cutting and Bulking Turn a calorie target into grams of protein, carbs and fat — for cutting or bulking. Read the guide → How to Measure Your Body Fat Percentage The tape, caliper, BIA and DXA methods compared — plus healthy ranges. Read the guide → How Long Does It Take to Lose Weight? The math behind realistic timelines, worked examples, and why loss slows down. Read the guide → How Much Protein Do You Need a Day? The g/kg targets for your goal, how to split protein across meals, and where to get it. Read the guide → How Many Carbs Should You Eat a Day? Carb targets for balanced, low-carb and keto — how to set your grams and pick quality carbs. Read the guide → Heart Rate Zones Explained What the five training zones mean and how to train in each with your heart rate. Read the guide → BMR vs TDEE vs RMR: What's the Difference? What BMR, RMR and TDEE each mean, how they connect, and which to use for your goal. Read the guide → Intermittent Fasting for Beginners How 16:8 and other methods work, how to start safely, and what breaks a fast. Read the guide → What Is a Good FFMI? The Natural Muscle Limit The FFMI ranges for men and women, the natural muscle limit, and how to read yours. Read the guide → Waist-to-Hip Ratio and Your Health What WHR says about health, the WHO risk thresholds, and how it compares to BMI. Read the guide → How to Predict Your Race Time Use a recent result to predict your finish time, and learn why longer predictions drift. Read the guide → How to Calculate Your One-Rep Max The Epley and Brzycki formulas, a worked example, and how to train with %1RM. Read the guide → What Is Lean Body Mass and Why It Matters LBM vs muscle mass, the formulas behind it, and how to keep it while dieting. Read the guide → How Much Should You Weigh? An Honest Answer Healthy weight ranges by height, where "ideal weight" formulas come from, and better signals. Read the guide → What Is a Good Waist-to-Height Ratio? The "half your height" rule, the NICE risk bands, and how WHtR compares to BMI. Read the guide → How Much Sleep Do You Need? By Age CDC sleep recommendations by age, what cycles do, and honest advice on sleep debt. Read the guide → How Many Steps a Day Do You Really Need? Where 10,000 steps came from and what the research actually shows by age. Read the guide → What Is a Calorie Deficit? The Simple Science The one mechanism behind all fat loss, how it works, and how to size it safely. Read the guide → How Many Calories Does Walking Burn? Body weight and pace decide almost everything — here is the honest MET math, in charts. Read the guide → What Is a Good Running Pace? Averages by Level Average easy-run and 5K paces by level, age and sex — and how to find yours. Read the guide → How Is a Due Date Calculated? A Simple Guide Naegele's rule, ultrasound dating, and why only about 4-5% of babies actually arrive on the due date. Read the guide → How to Speed Up Your Metabolism: What Works The honest, evidence-based guide to boosting metabolism — and what barely works. Read the guide →