Caffeine is an ingredient in many weight loss supplements, and is often promoted as an appetite suppressant. But how well does it work?
People who drink caffeine-containing beverages have a lower body mass index (BMI) than people who don’t, and some research suggests that caffeine can increase your metabolism or suppress your appetite. Researchers at SUNY Buffalo State College decided to study whether caffeine can, in fact, influence food intake and appetite.
They managed to find 50 adults who were willing to give up their regular caffeine intake for 24 hours on three separate occasions over three weeks to participate in the study. The participants visited the lab each week and were given a juice to drink. On one occasion, the juice contained a 3 mg per kg of body weight of dose of caffeine, the equivalent of 12 ounces of coffee. On another it contained 1 mg per kg of caffeine, the equivalent of four ounces of coffee. On another visit, it contained no caffeine at all. The different amounts of caffeine and the control no-caffeine dose were given randomly.
After drinking their juice — with or without caffeine — participants were offered a buffet breakfast and told to eat as much or as little as they wanted.
People who drank the juice with 1 mg/kg of caffeine added ate about 70 fewer calories at breakfast compared to those who drank the juice with the higher dose of caffeine or juice with no caffeine. However, the people who ate less at breakfast made up those calories later in the day. Appetite was not affected by caffeine intake, and the BMIs of the participants had no effect on how much they ate or their appetite.
Caffeine has its health benefits, but appetite control and weight loss don’t appear to be on the list. In a statement on the study, researcher Carol DeNysschen put it this way, “This study, by nature of its rigorous design, reinforces the importance of good eating habits and not relying on unsupported weight loss aids or unhealthy practices.”
The study was published in the Journal of the Academy of Nutrition and Dietetics.