Does Coffee Help You Lose Weight? Small Study Offers New Insight

Many self-proclaimed diet gurus have recommended knocking back a shot of espresso in the morning to suppress appetite and boost weight loss. But researchers at Buffalo State College, part of the State University of New York system, found that caffeine does not dampen the appetite in any meaningful way or help us shed pounds.

In a small, randomized control study published Thursday in the Journal of the Academy of Nutrition and Dietetics, the researchers examined the effect of caffeine on the appetite of 50 healthy adults aged between 18 and 50. People who had never drank coffee, had adverse experiences consuming caffeine or smoked were excluded.

Participants visited the lab once a week for a month. For each visit, they drank juice containing the amount of caffeine equivalent to 4 ounces of coffee (1 mg/kg), 8 ounces of coffee (3 mg/kg) or no coffee as a placebo. After half an hour, the researchers instructed the participants to eat as much as they liked from a buffet stocked with common American breakfast foods, such as cereal and hot sandwiches.

For the rest of the day, the individuals documented what they ate, and they filled out an online survey every hour detailing their appetite until midnight or bedtime, whichever came first.

The team found that participants who consumed the juice with the amount of caffeine equivalent of 4 ounces of coffee ate 70 fewer calories at breakfast than participants who consumed the equivalent of 8 ounces of coffee or none. This dip in calorie intake didn't last, however, and the participants ended up making up the deficit later in the day. And there was no difference in self-reported appetite between those who did and didn't consume caffeine.

The authors of the study noted the participants' body mass index did not affect how much they consumed or their appetite.

Read more: Drinking this much coffee could help keep your heart healthy, study suggests

"The take-home message is that caffeine is frequently studied in terms of its impact on weight management, and although there are some small studies which suggest a potential impact on weight, there are hundreds more which disprove this," Aisling Pigott, a dietitian and spokesperson for the British Dietetic Association, told Newsweek. "From a scientific perspective, there is no current role for caffeine as an appetite suppressant or metabolic aid."

Whether it's caffeine or other items marketed as quick answers to weight loss, such as turmeric, Pigott said, "there is no magic weight-loss solution or pill. Weight and our relationship with food and eating is much more complex than this."

The SUNY Buffalo State team is the latest to question whether drinking coffee has health benefits. For instance, past studies have suggested individuals who regularly drink coffee have a lower BMI on average than those who don't, the researchers noted.

And a study published in June in the journal PLOS Biology found that drinking four cups of coffee a day could start a process in the body that protects heart cells. The amount of caffeine equivalent to four cups of coffee affected a protein called p27, which is present in the mitochondria, or powerhouses, of major cells in the heart. Coffee was also found to protect cells from death and help the heart recover after cardiovascular events, like heart attacks.

"There is something to this four or more cups of coffee which seems to be protective," study author Judith Haendeler, of the IUF-Leibniz Research Institute for Environmental Medicine in Germany, told Newsweek. But, she warned, "don't [just] take caffeine pills, stop eating a healthy diet and exercising and be a couch potato."

This article has been updated with comment from Aisling Pigott.