Nutrition Science

What the Evidence Actually Says About What to Eat

Macronutrients, Metabolism, Myths, and the Science of Feeding a Human Body

A free, comprehensive textbook for anyone who eats.

Published by DataField.Dev

License: Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)

You are free to share and adapt this work for any purpose, including commercially, provided you give appropriate credit and license your contributions under the same terms.

Important: this book is education, not medical advice

This textbook explains what nutrition research shows. It cannot know your laboratory values, your medications, your medical history, your budget, your culture, or your circumstances — and it is those things, not the general literature, that determine what any individual person should do.

Nothing in this book is a prescription, a dosing protocol, or a treatment plan.

Consult a registered dietitian (RD/RDN) and your physician before making significant dietary changes, and especially if you are pregnant or breastfeeding, feeding an infant or young child, managing a chronic condition such as diabetes, cardiovascular disease, kidney disease, or celiac disease, taking any medication, recovering from illness or surgery, or living with — or recovering from — an eating disorder.

Where the stakes are highest, this book flags it directly in ⚠️ When to see a professional callouts. Please treat those as the author speaking in her actual clinical voice, because she is.

Nutrition guidance also changes as evidence accumulates. Reference intakes, guidelines, and recommendations cited here point you to their primary sources so you can check whether they have moved since publication. They will. That is not a flaw in the science. It is the science working.

For everyone who has stood in a grocery aisle holding two boxes, trying to remember which one the internet said would kill them this month.