It is a good Saturday morning, birds are chirping, the sun shines so brightly, and having a cup of coffee is the best way to start the day.
Americano, latte, cappuccino, whatever it is, coffee in the morning never goes wrong. But have you ever felt a sudden hunger after drinking coffee? Your stomach is growling and it feels like your gastric acid is going to reflux.
How can that such thing happen?
As we all know, caffeine is one of the substances that is contained in coffee. Caffeine is a substance that belongs to the purine alkaloid group and can be derived from plants, such as coffee, tea, and cocoa. As a stimulant, one of the most well-known of caffeine is to keep us awake longer. But other than that, caffeine also can stimulate the secretion of gastric acid—the acid that activates digestive enzymes in our stomach. The bitter taste of caffeine is indicated to play role in the bitter-substance evoked chemosensory mechanism.
Chemosensation regulates gastric acid secretion at three sites: (1) oral/mouth, (2) gut through induction of gastrin and/or histamine release, (3) gut by modulating acid production in parietal cells—the cells that regulate the production and secretion of gastric acid.
As we drink coffee, the caffeine will stimulate the production of gastric acid so there will be a rise in the gastric acid level. This phenomenon—the rise of gastric acid—also occurs during food digestion. Whenever we think, smell, or see food, our nervous system processes these stimuli and as the output, gastric acid production will increase and after that, as the food enters the stomach, digestion will start. More acid will be secreted and the mixing process by stomach muscle will start.
This might be the reason why we feel hungry after drinking coffee. The high level of gastric acid is recognized by our body as the start of food digestion but in fact, there is no food to digest meanwhile our stomach motility is increased due to the high level of gastric acid.
This is one of the reasons why we often feel hungry after drinking coffee. But not everyone experiences this kind of thing since metabolism and hormone regulation may vary in each individual due to genetic variation.