Eating behaviour
All the behaviours linked to food intake, determined by physiological hunger but also by emotions, environment and social habits.
Eating behaviour cannot be reduced to a response to an energy need. Three systems overlap: homeostatic regulation (hunger and fullness driven by hormones), hedonic regulation (pleasure and reward), and social and cultural determinants.
These are two distinct brain circuits, and this explains a universal experience: you can still want a dessert when you are no longer physiologically hungry. The hedonic system can override fullness signals, especially when faced with foods that combine sugar, fat and salt.
Environment weighs more than willpower. This is the most consistent finding of research on the subject: the size of portions and tableware, how visible food is, the number of people at the table and distraction during the meal measurably influence how much is eaten, without the eaters being aware of it. Acting on your surroundings is more effective than relying on self-control.
Finally, normal variations (occasional snacking, a festive meal, an emotional craving) should be distinguished from eating disorders (anorexia, bulimia, binge eating), which are medical conditions requiring specialist care. A relationship with food that causes lasting distress warrants professional advice.