Couples in their 20s had their heart rates and brains monitored whilst they first melted chocolate in their mouths and then kissed. Chocolate caused a more intense and longer lasting "buzz" than kissing, and doubled volunteers' heart rates. The research was carried out by Dr David Lewis, formerly of the University of Sussex, and now of the Mind Lab. Experts, concerned at growing levels of obesity throughout the developed world, warn that chocolate should only be consumed in moderation. Dr Lewis said: "There is no doubt that chocolate beats kissing hands down when it comes to providing a long-lasting body and brain buzz. "A buzz that, in many cases, lasted four times as long as the most passionate kiss." He said substances in chocolate were already known to have a psychoactive effect, but that allowing it to melt on your tongue could be the secret to maximising the buzz. The volunteers, all aged in their 20s, had electrodes attached to their scalps and wore heart monitors during the two tests. The researchers compared their resting heart rates with those during the chocolate and kissing tests. Although kissing set the heart pounding, the effect did not last as long as that seen with the chocolate, which increased heart rates from a resting rate of about 60 beats per minute to 140. The study also found that as the chocolate started melting, all regions of the brain received a boost far more intense and longer lasting than the excitement seen with kissing. Although women are generally thought to be bigger fans of chocolate than men, the research found the same reactions to chocolate in both sexes. Dr Lewis said: "These results really surprised and intrigued us. "While we fully expected chocolate- especially dark chocolate - to increase heart rates due to the fact it contains some highly stimulating substances, both the length of this increase together with the powerful effects it had on the mind were something none of us had anticipated." Psychologist Sue Wright said: "Chocolate contains phenylethylamine which can raise levels of endorphins, the pleasure-giving substances, in the brain. "It also contains caffeine which has a stimulatory effect on the brain. "This would explain why chocolate can give people a buzz, and why people can become addicted to it." The research used a new 60% cocoa dark chocolate from Cadbury, and a spokeswoman for the chocolate makers said: "You'd think people would be shy about kissing in a laboratory, but that wasn't the case at all. We're not talking about a quick peck here." The Mind Lab is funded by members of the food industry, although no firm can be linked to any individual study. Source: bbc