A person' s intake of refined sugar and of foods that break down into sugars during digestion is the dietary source of virtually all of the glucose (a type of sugar) that reaches that person' s bloodstream
Coffee, however, which itself does not break down into sugars during digestion, sometimes causes a person' s blood-glucose level to rise dramatically, even if the coffee is consumed without cream or any sweeteners
People with sedentary office jobs are more likely to drink large amounts of coffee and to have higher blood-glucose levels than are people with jobs requiring constant physical activity.