Fitness Guides

Science-Backed Fitness Guides

In-depth, evidence-based guides written for real people. Each guide explains the science, the formulas, and what to actually do with the information.

The Complete BMI Guide

Understand Body Mass Index — from the WHO formula and healthy ranges to its major limitations for athletes and different ethnicities.

Everything about caloric deficits, sustainable fat loss, macronutrient strategies, and overcoming weight loss plateaus.

Master the single most important number in nutrition — your TDEE — and learn how to use it for fat loss, maintenance, or muscle gain.

The definitive guide to macronutrients — what they do, how to calculate your targets, and how to set up your diet for any goal.