You are fine at 11:30, ravenous at 12:30, and then, if something gets in the way of lunch, oddly fine again at 14:00. Hunger is not a fuel gauge that only goes down. It behaves more like a tide, and knowing that makes a first fasting window (or just a late lunch) much less scary.
Ghrelin is a hormone made mostly in the stomach that nudges appetite upward. It tends to rise before meals and fall after eating. The interesting part is that the rhythm is partly learned. In a small pilot study of six healthy adults who were kept fasting for 24 hours, ghrelin still rose and fell at the times people normally eat, even though no food arrived. The authors read this as a sign that the brain, not just the stomach, helps set when hunger shows up.
That study is tiny, so treat it as a clue rather than a rule. The evidence is also mixed: in an 8-week trial of alternate-day fasting in adults with obesity, ghrelin rose during fasting but hunger ratings were not linked to it. Hunger is also shaped by sleep, stress, the smell of food, what you ate last time and who is sitting next to you.
Hunger often arrives on a schedule you trained, so a first wave at your usual meal time is a habit talking, not an emergency.
If you are trying a longer gap between meals, a few plain things make the waves easier to live with. None of them is a trick, and none is a substitute for eating when you need to.
Everything above is general information, not medical advice. The NHS advises that people with a history of eating disorders, people who are pregnant or breastfeeding, and people with diabetes should not delay or skip meals, and that anyone on medication should speak to their GP team before changing how they eat. If any of that applies to you, or you are under 18, talk to a doctor or dietitian first. Skipping meals is also not a way to "make up" for eating more earlier, and a pattern that leaves you thinking about food all day is not working for you. Fasting is one option among many, and eating regular meals is a perfectly good way to eat well.