For some, that first cup of coffee in the morning is something of a sacred ritual—just you, your coffee, and a blessed quiet moment in which to enjoy it. While many have tried to replace coffee with green tea, it’s still easily the most popular morning energy boost. But there is one thing you should remember not to do: drink it on an empty stomach.
What happens when you drink coffee on an empty stomach?
Cortisol spikes and hormonal stress
Coffee, thanks to its caffeine content, stimulates the production of cortisol—also known as the stress hormone. Normally, cortisol levels are at their highest in the morning when we wake up, but drinking coffee on an empty stomach can further increase them, potentially causing an overload of stress on the body. Excess cortisol can also affect mood, leading to nervousness, anxiety, or irritability. Over time, too much cortisol can alter metabolism and affect sleep cycles.
Stomach acidity and poor digestion
Drinking coffee on an empty stomach can increase gastric acidity. Coffee stimulates the production of hydrochloric acid in the stomach, which, if not balanced by some food, can irritate the gastric mucous membranes. This can lead to a burning sensation, gastroesophageal reflux (when stomach acid flows back up the tube that connects the mouth and the stomach), and gastritis – especially in those who are already prone to stomach problems. Acid can erode the gastric mucosa (the slippery protective layer that lines the inner surface of the stomach) more easily when it is not protected by food, increasing the risk of inflammation.
In addition to acid production, caffeine also stimulates intestinal motility. When consumed on an empty stomach, it can cause abdominal cramping, bloating, and bowel problems—especially in those with a sensitive gut or who suffer from irritable bowel syndrome (IBS). Drinking coffee on an empty stomach can accelerate intestinal transit, causing discomfort and digestive upset. Not what we want.
Glycemic spikes caused by caffeine
Drinking coffee on an empty stomach can also alter blood sugar levels, thanks to the caffeine causing temporary glycemic spikes. Without breakfast to stabilise the blood sugar, this spike can be followed by a sudden drop in blood sugar levels, potentially leading to fatigue, hunger, and irritability. In some cases, these sorts of spikes can be problematic for those with diabetes or blood sugar-related disorders.
How to optimize your morning coffee
So, now we know that regularly drinking coffee on an empty stomach can have some pretty unpleasant side effects. To avoid these, it’s best to enjoy your morning cup with a balanced breakfast (think protein, fiber, and fat), that can help to protect the walls of your stomach.
TLDR? Think breakfast, then coffee.
