Caffeine: the universal energy fuel to get through Mondays. Unfortunately, it is not quite the (work) life-sustaining substance we thought: A new study has found the side effects of caffeine include desensitizing our taste buds, making us need ever more sugar or sweetener to taste the same level of sweetness.

“When you drink caffeinated coffee, it will change how you perceive taste — for however long that effect lasts,” said senior author Robin Dando. “So if you eat food directly after drinking a caffeinated coffee or other caffeinated drinks, you will likely perceive food differently.”

The study examined two groups for the effects of caffeine on taste; one sampled decaffeinated coffee with 200 milligrams of caffeine and sugar added (think: one morning-strong cup of coffee). The other group drank the decaffeinated coffee with just the same amount o f sugar added. Neither knew which type of coffee they had received. The researchers observed that people who drank the caffeinated coffee rated it as less sweet than the decaf drinkers, suggesting the caffeine had desensitized their sense ofd taste. (There was no effect on other tastes, like sour or salty.)

Participants were then asked to describe their level of alertness and to guess the amount of caffeine in their coffee. Interestingly, participants who had the decaf coffee rated their level of alertness similar to those who had the caffeinated coffee. The participants were also unable to guess whether they had the caffeinated or decaffeinated sample of coffee.

“We think there might be a placebo or a conditioning effect to the simple action of drinking coffee. Think: Pavlov’s dog,” Dando said, referring to the classic experiment that conditioned a dog to salivate hungrily at the sound of a tuning fork. “The act of drinking coffee — with the aroma and taste — is usually followed by alertness. So, the panelists felt alert even if the caffeine was not there.”

So, if you are craving a cherry pie to go along with your coffee in the morning, it’s not (only) because of Twin Peaks. Consider switching to decaf; it just might give you the same energy boost — but without leading you to unwittingly consume more sugar or sweetener.