Before you start

This is a short book. You can read it in two or three evenings.

It's about one habit. Partway through a meal you've had enough. You may notice it and you may not. Either way you carry on, because there's food left on the plate or in the dish, and it's good, and stopping would feel like giving something up. Twenty minutes later you're on the sofa with your waistband undone, wishing you'd stopped when you were comfortable.

This isn't a diet book. It doesn't ban any food, count anything, or tell you what you should eat. It makes no promise about your weight. I don't think pudding is a moral failing, and I think a big Christmas dinner is one of the good things in life. The book has one target, which is the part of a meal that comes after you've had enough. I'll argue that this part gives you much less than it seems to, and that stopping before it costs you much less than it feels as if it will.

Three cautions before we start, and they matter more in this book than in most.

The first is about eating disorders. This book is written for ordinary overeating at ordinary meals. Some people's eating is a different thing. They regularly eat a large amount in a short time and feel unable to stop. It often happens alone or in secret, and they feel ashamed or disgusted afterwards. That may be binge eating disorder. It's a recognised illness, it's treatable, and the NHS advice is to see a GP as soon as you can. The same goes if you ever make yourself sick after eating, use laxatives to make up for it, or go long periods eating very little. A book about habits isn't the right tool for any of those, and some of its suggestions could make things worse. If you've had an eating disorder in the past, please talk to whoever treats you before trying anything here.

The second is medical. If you have diabetes, are pregnant, or have any condition where a clinician has told you when or how much to eat, their advice comes before mine. Some medicines increase appetite. If you think one of yours does, raise it with whoever prescribed it, and don't stop taking it.

The third is about children. Nothing in this book is meant to be applied to a child's plate. Chapter 4 touches on why.

The middle chapters each take one belief that keeps the fork moving. "It still tastes good." "It'd be a waste." "I don't feel full yet." Each is partly true, and I'll try to give it its due before I argue with it. The notes at the back give the studies I've relied on and their limits. The rest is my own reasoning, and I'll say so where it matters.