FitCalcs

Fitness & Health Guides

Science-based articles to help you understand the numbers behind your fitness goals.

How to Calculate Your BMI (And Why It's Not Enough)

Learn how BMI is calculated, what the ranges mean, and why body fat percentage may be a better measure of health. Free BMI calculator included.

2026-03-257 min read

TDEE Explained: Your Complete Guide to Daily Calories

What is TDEE? How is it calculated? Learn the Mifflin-St Jeor formula, activity multipliers, and how to use TDEE for weight loss, maintenance, or muscle gain.

2026-03-258 min read

How Much Protein Do You Really Need? Science-Based Guide

The definitive guide to daily protein intake for muscle building, fat loss, and general health. Based on the latest research, not bro science.

2026-03-259 min read

Is 1200 Calories Enough? The Truth About Very Low Calorie Diets

Why 1200-calorie diets are popular, when they're dangerous, and how to find your actual minimum calorie needs for safe, sustainable weight loss.

2026-03-257 min read

BMI vs Body Fat Percentage: Which Matters More?

BMI is simple but flawed. Body fat percentage tells the real story. Learn when to use each, their limitations, and how to measure both for free.

2026-03-256 min read

Zone 2 Training: The Complete Guide to Low-Intensity Cardio

Why Zone 2 is the most important training zone for health and longevity. How to find your Zone 2 heart rate, how often to train, and the science behind it.

2026-03-258 min read

How to Calculate Macros for Weight Loss: Step-by-Step

A simple, no-nonsense guide to calculating your macronutrient targets for fat loss. Protein, carbs, and fat ratios explained with real examples.

2026-03-258 min read

Body Recomposition: How to Build Muscle and Lose Fat at the Same Time

Yes, you can build muscle while losing fat. Learn who it works for, the science behind it, and exactly how to set up your calories and training.

2026-03-259 min read

VO2 Max: Why It's the Best Predictor of Longevity

Low VO2 max means 5x higher mortality risk. Learn what VO2 max is, how to estimate yours without a lab, and proven ways to improve it for a longer, healthier life.

2026-03-278 min read

Rucking for Fitness: Complete Beginner's Guide

Rucking burns 2-3x more calories than walking with minimal injury risk. Learn how to start, what weight to use, progression tips, and common mistakes to avoid.

2026-03-277 min read

Grip Strength and Longevity: What the Science Says

Grip strength predicts cardiovascular death better than blood pressure. Learn why it matters, how to test yours, and simple exercises to improve it.

2026-03-277 min read

Intermittent Fasting for Beginners: The Complete Guide

Everything you need to know about intermittent fasting: protocols (16:8, OMAD, 5:2), benefits, who should avoid it, and how to start without feeling miserable.

2026-03-279 min read

The Keto Diet: A Complete Guide for Beginners

What is keto, how does ketosis work, what to eat and avoid, dealing with keto flu, and whether it's sustainable long-term. Science-based, no hype.

2026-03-279 min read

How Accurate Is BMI? The Truth About Its Limitations

BMI misclassifies about 30% of people. Learn where it fails, why it was never designed for individuals, and what better alternatives exist.

2026-03-277 min read

What Heart Rate Zone Actually Burns the Most Fat?

The fat burning zone is real but misunderstood. Learn the science behind fuel utilization, why Zone 2 matters, and the 80/20 rule for optimal fat loss.

2026-03-278 min read