If you drain your first coffee of the day while instantly planning for your next one, that quest for a caffeine hit might be due to your genes.
As part of an in-depth new study, researchers at the University of Edinburgh and the University of University of Trieste, Italy, looked at the DNA of around 3,000 coffee drinkers in the Netherlands and Italy.
According to the Daily Mail, the researchers asked participants to record how many cups they consumed per day, and matched the results against who out of the survey participants had gene PDSS2 - a variation that reduces the body's ability to break down caffeine.
The survey found Italian people with the DNA variation consumed, on average, one less cup of coffee per day than those without it.
While those in the Netherands where less affected by the gene difference.