The Glucose Never Lies

Making diabetes science work in real life for people living with type 1 diabetes

An independent education platform that translates complex diabetes science into clear, practical understanding. Built by clinicians and people living with type 1 diabetes, grounded in peer-reviewed evidence, and designed to help you explore how glucose really works.

What is The Glucose Never Lies?

GNL is an independent educational platform for type 1 diabetes. It explains the mechanisms behind glucose behaviour — why insulin, food, activity, and physiology interact the way they do — so that you can build your own understanding through observation, exploration, and conversation with your care team.

Everything here is built around one idea: that understanding the mechanisms behind glucose behaviour, and testing that understanding against your own CGM data, is the most powerful form of diabetes education. GNL does not tell you what to do. It explains what tends to happen on average, describes the science, and invites you to explore. Your care team provides the individual clinical guidance. Your CGM provides the feedback. The learning happens in the space between. Read our full disclaimer.

Type 1 Diabetes Education Evidence-based

Where to start

New here? Start with Foundations

The Foundations sequence covers the essential building blocks of type 1 diabetes — insulin, carbohydrate, activity, CGM, and glucose patterns. The rest of the site assumes this knowledge is in place.

Explore the Foundations

Know the basics? Explore the Guides

The GNL Guides go deeper — covering insulin on board, exercise physiology, CGM technology, AID systems, and more. Each guide explains the mechanism and invites you to test it against your own data.

Browse the GNL Guides

Explore the platform

The GNL Podcast

Over 34 episodes covering the science, technology, and lived experience of type 1 diabetes. Hear from world-leading researchers, clinicians, and people living with the condition every day.

Listen to the Podcast

GNL Educational Explorers

Interactive tools built around the four majors that drive glucose behaviour. Explore AID algorithm logic, activity-based glucose response, hypo and hyper management, and exercise carbohydrate estimation — using your own numbers.

Open the Explorers

Inspiring Stories

Real experiences from people living with type 1 diabetes — exploring what it means to manage a condition that never takes a day off, and finding strength in shared understanding.

Read Inspiring Stories

Latest episodes

See all Podcast Episodes

What’s new

The IOB Trade-Off

How AID systems see insulin differently — and why the gap between device-reported IOB and true insulin exposure matters more than most people realise.

Read the article

Insulin on Board — the GNL Guide

A complete explanation of what insulin on board is, how it is calculated, and why understanding it is essential for anyone using an AID system or making manual correction decisions.

Read the IOB Guide

The GNL Explorers — built with Phil Hayes

Interactive tools that let you put in your own numbers and see what the evidence says should happen — then compare it against your CGM. The story of how they were built.

Open the Explorers

The Glucose Never Lies® Team

GNL is built by a team of clinicians, researchers, and creators united by science, storytelling, and lived experience.

John Pemberton and Anjanee Kohli

Registered Dietitians and Diabetes Specialists at Birmingham Women’s and Children’s NHS Foundation Trust — the clinical and creative core of GNL.

Phil Hayes — Lead Developer

The lead developer behind the GNL Explorers and the platform’s technical infrastructure. Phil designed and built the interactive tools that let you explore glucose behaviour with your own numbers.

Scientific Advisory Team

Dr Dessi Zaharieva, Professor Othmar Moser, and Dr Adrian Brown provide independent scientific review and challenge on every GNL output.

Meet the full GNL team

Contact

We welcome opportunities for consultancy, educational projects, speaking engagements, and content development.

john@theglucoseneverlies.com — Consultancy, speaking, and educational projects anj@theglucoseneverlies.com — Content creation and development

Stay connected

Stay up to date with new episodes, visuals, and educational content:

We invite everyone who reads, listens, or learns with us to judge our work by its accuracy, transparency, and value to the diabetes community. That is what The Glucose Never Lies® stands for, and always will.

About GNL and Disclaimer Meet the GNL Mentors