Why we can’t resist a sinful, dark chocolate cake

Washington: Scientists have revealed why is it that despite being on a strict diet, some of us can’t help taking a bite of that sinful, dark chocolate cake.

Professor Ray Dolan and his colleagues have shown that increased levels of dopamine – a chemical in the brain involved in mediating reward, motivation, and learning through reinforcement - affects our will power and makes us act impulsively.

The research may explain why people affected by conditions such as Attention Deficit/Hyperactivity Disorder (ADHD) show extremely impulsive behaviour or why such behaviour can be a potential negative side-effect of L-dopa, a drug used to help alleviate the symptoms of Parkinson`s disease.

In a study, the team administered low dose of L-dopa and then placed the subjects on a placebo.

The results showed that when asked to make a choice, say, receiving 15 pounds in two weeks, or a ``larger, later`` option, such as receiving 57 pounds in six months, every subject was more likely to behave more impulsively – choosing the ``smaller, sooner`` option when the levels of dopamine were high.

"Lowering dopamine levels may be able to reduce impulsivity, but we need to be certain that this didn``t come at the expense of other, important functions," explains Dr Alex Pine, first author of the study.

The study is published today in the Journal of Neuroscience.