We actually tell the stomach when to be hungry. This occurs through our eating habits. When we eat three meals a day at regular times, the stomach becomes conditioned to expect food at those times.
…People who never eat breakfast don’t have hunger pangs in the early morning. People who do, do. If you fast for over three days, the hunger pangs and growling disappear. The abdomen feels flat, quiet, and comfortable. This tells us that the stomach hunger is not a permanent, solid feature of our lives, one whose urging we must obey. It’s our body hunger that is more fundamental and important to learn to feel.
—Jan Chozen Bays MD, Mindful Eating: A Guide to Rediscovering a Healthy and Joyful Relationship with Food