Millions of us cannot start the day without our coffee. Is that such a bad thing? According to several studies, regular coffee reduces our risk of developing diabetes, mental illness, many cancers, and overall mortality. However, no scientific studies have looked at whether coffee might affect appetite.

Matt Schubert, a Ph.D. candidate, and Associate Professor Ben Desbrow, both from the Centre for Health Practice Innovation, Griffith University, Australia, set out to determine what effect coffee might have on appetite.

That is the question being asked by PhD candidate Matt Schubert and Associate Professor Ben Desbrow from Griffith University's Centre for Health Practice Innovation.

Schubert said:

"Anecdotally, people have reported feeling less hungry after consuming a coffee, and some people prefer to have coffee instead of breakfast.

However, when you observe what people pair with their coffees in a coffee shop setting, you see consumption of high-fat, sweet foods. What we want to explore is whether there is an effect of coffee on food preference and what the implications of this might be for weight control."

The researchers are currently conducting four trials. Some of the participants are given two coffee drinks - one during their breakfast and the other two hours later, while the rest are having coffee-free mornings or just caffeine alone.

The investigators monitor the volunteers from breakfast to lunch time (4 to 5 hours) and regularly assess their perceptions of satiety (fullness), hunger, and desires for certain foods to examine appetite responses.

A small cup of coffee
Coffee appears to reduce appetite
While emphasizing that the trials are still ongoing, Schubert explains that the team have so far observed less hunger and a greater sensation of fullness among those having two coffees. "A trend we're not observing with decaffeinated coffee or caffeine alone for some individuals. This may be important for weight control, as any decrease in appetite could help reduce food intake."

If an individual consumes less energy while maintaining or raising energy expenditure through physical activity, this could be used as a strategy to help people maintain a desirable body weight, the researchers believe.

Schubert and Desbrow are currently recruiting participants for the ongoing study. They are looking for healthy, non-smoking 18 to 45 year-olds with no chronic diseases or special diets.

Coffee may help you live longer

Researchers from the University of Athens Medical School believe that coffee improves cardiovascular health and increases longevity - boiled Greek coffee to be exact. Their findings, which were published in Vascular Medicine (March 2013 issue), were based on observations made among the residents of Ikaria, a Greek island. Ikarians say they have the longest lifespans in the world.

Too much coffee can make you hear things that are not there - a team from La Trobe University, Australia, reported in Personality and Individual Differences (June 2011 issue) that too much coffee can trigger auditory hallucinations.

Professor Simon Crowe and colleagues randomly selected 92 volunteers to either a high or low stress condition, and a high or low caffeine condition. They then listened to white noise and were asked to report whenever they heard the song "White Christmas". Humans hear white noise as a fuzzy sound, it contains every frequency within the range of human frequency.

A significantly higher percentage of participants with high caffeine levels or high stress reported hearing the White Christmas song - even though it was never played.

Professor Crowe said: "There is a link between high levels of stress and psychosis, and caffeine was found to correlate with hallucination proneness. The combination of caffeine and stress affect the likelihood of an individual experiencing a psychosis-like symptom."

Written by Christian Nordqvist