This is not a diet book A generation ago, most people did not need a book to explain the difference between food and junk. Real food was what you cooked at home or ate at a café that sourced from local markets. Sweets and crisps were occasional extras, not daily staples. Portions were smaller. Meals were slower. Movement was built into life. Today, we live in a different world. Rates of obesity, type 2 diabetes, fatty liver disease, and heart disease have risen sharply in just a few decades. These are not simply the result of people suddenly becoming lazy or greedy. They are symptoms of a food environment and lifestyle that have changed faster than our biology can adapt. This book has three aims: To help you clearly distinguish real food from junk food , even when marketing tries to blur the lines. - To show you how the modern food environment undermines your health—and what you can realistically do about it. - To guide you in building a sustainable, enjoyable way of eating and living that fits your reality, not an idealised fantasy. Why “the 21st century” matters Your grandparents did not have to navigate: 24/7 food availability, - delivery apps that bring highly processed meals to your door within minutes, - targeted advertising based on your browsing habits, - food designed by teams of scientists to hit the “bliss point” of sugar, fat, and salt, - working days spent in front of screens, with stress but little movement. Health advice that ignores this reality is unhelpful. Telling people to “just have more willpower” in an environment engineered to make overeating and junk food consumption the default is like telling someone to “just swim harder” in a rip current. This book respects the world you actually live in. It recognises the pressures of money, time, culture, and family. It acknowledges that change is hard, and that you may not control everything—but you can control enough to make a meaningful difference. What you can expect In the chapters ahead you will: Understand how our health got to this point and why so many people struggle. - Learn to recognise real food and junk food quickly, in any setting. - Decode food labels and marketing claims that are designed to mislead. - Build simple frameworks for planning meals, shopping, and cooking. - Discover how sleep, movement, and stress shape your food choices. - Develop habits that last longer than any short-term diet. You will also find recipes, templates, and checklists designed for real life—busy schedules, tight budgets, children, holidays, and social pressure. A note on diversity of diets People thrive on a variety of eating patterns: Mediterranean, traditional Asian, African, Latin American, vegetarian, flexitarian, and more. This book does not promote a single cultural or ideological diet. Instead, it focuses on principles that can be adapted: more whole foods, fewer ultra-processed foods; - more plants, better-quality proteins, smarter fats; - balance, not extremes. Use these principles to improve the way you already like to eat, rather than to adopt a completely foreign style that you will abandon after a few weeks.