If your commute to work involves a stop at the coffee shop, be cautious – you might be tempted to pick up a sweet treat, too.

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Research suggests that caffeine may dampen our ability to taste sweet foods, increasing our preference for them.

Researchers have found that caffeine – the key stimulant in coffee – dulls our ability to taste sweet food and drinks, which may actually increase our desire for them.

What is more, the team found that simply the action of drinking coffee – regardless of whether the beverage is caffeinated – may increase alertness.

Senior study author Robin Dando, of the Department of Food Science at Cornell University in Ithaca, NY, and colleagues recently reported their results in the Journal of Food Science.

Coffee is undoubtedly a popular beverage in the Americas. Around 54 percent of us drink coffee on a daily basis, and as a nation, we spend around $40 billion on the beverage annually.

Given the potential health benefits of coffee consumption, it is no wonder we can’t seem to get enough. A study reported by Medical News Today earlier this year, for example, linked daily coffee intake with reduced risk of liver cancer, while more recent research found that the beverage could help us live longer.

The new study from Dando and colleagues, however, suggests that we should be cautious of what we are eating alongside our cup of joe, as the beverage may increase our preference for sugary treats.

The researchers came to their findings by enrolling 107 adults and randomly assigning them to one of two groups.

One group consumed coffee containing 200 milligrams of caffeine – the equivalent of a strong cup of coffee – while the other group consumed decaffeinated coffee supplemented with quinine, making it taste just as bitter as the caffeinated coffee. Both groups had sugar added to their beverage.

Participants were unaware of which type of coffee they were drinking.

The team found that subjects who consumed the caffeinated coffee rated the beverage as being less sweet than those who drank the decaffeinated coffee.

Additionally, after consuming a sucrose solution, participants who consumed caffeinated coffee said the solution tasted less sweet, compared with those who drank decaffeinated coffee.

Dando and colleagues note that caffeine blocks adenosine receptors in the brain, which increases alertness. At the same time, blocking these receptors reduces a person’s ability to taste sweet foods and drinks. In turn, this may increase cravings for such products.

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

In a second experiment, subjects were once again randomized to receive either caffeinated or decaffeinated coffee.

Each participant was asked to rate their alertness before and after consuming the beverage, as well as estimate the amount of caffeine that was in their drink.

The researchers found that participants were not only unable to determine whether they were drinking caffeinated or decaffeinated coffee, but both groups reported the same increase in alertness after consumption.

Dando and colleagues say their findings indicate that simply drinking a cup of coffee may induce a placebo effect.

“Think Pavlov’s dog. 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,” explains Dando.

What seems to be important is the action of drinking that coffee. Just the action of thinking that you’ve done the things that make you feel more awake, makes you feel more awake.”

Robin Dando