Guides

Our calculators hand you a number. These guides explain what to do with it. Each one is written in plain English, grounded in mainstream health and fitness science, and linked to the exact tools you'll need along the way.

How to Lose Weight Sustainably (Without Crash Dieting)

The calorie-first approach to losing fat and keeping it off: how to set a deficit you'll barely notice, protect your muscle with protein, track honestly, and break through stalls without starving yourself.

Understanding Your Metabolism: BMR, TDEE and What They Mean

What metabolism actually is, how BMR and TDEE differ, why some people seem to burn more, and how to turn your numbers into the right amount to eat — plus the truth about the "slow metabolism" myth.

Protein and Macros Explained: How to Set Your Targets

What protein, carbs and fat each do, how much protein you really need, and a simple way to split your calories into macro targets that fit your goal without overcomplicating it.

Is BMI Accurate? BMI vs Body Fat and Better Ways to Track

What BMI gets right, where it misleads, and the better numbers — body fat percentage and waist-based ratios — for understanding your body composition.

Heart Rate Zones Explained: How to Train by Heart Rate

The five heart rate zones, how to find yours in real beats per minute, and the 80/20 balance of easy and hard training that actually builds fitness.

Ovulation, Your Cycle and Due Dates: A Practical Guide

How the menstrual cycle works, when ovulation really happens, how to spot your fertile window, and how pregnancy due dates are estimated.

How Much Water Should You Drink a Day?

Why the "8 glasses" rule is a myth, how much water you actually need for your body and activity, and the simple signs that tell you whether you're hydrated.

More guides are on the way. Have a topic you'd like us to cover? Let us know.