The suspected culprit, in this case, is cortisol, which is known to raise blood glucose by releasing stored glucose.
If cortisol levels remain chronically high, this can lead to persistent high blood sugar levels and set the stage for type 2 diabetes.
There is the added problem of coffee relaxing the oesophageal sphincter, which can allow stomach acid to rise back into the oesophagus.
This condition, known as acid reflux, is a well-known irritant linked to the development of certain cancers, but evidence linking morning coffees to cancer is scarce.
Medicover Hospitals states: “[…] Experts warn that coffee should never be consumed in the morning when you wake up.