Exhibiting people evidence of the harm unhealthy habits do can motivate them to change.Researchers in Texas have reviewed a number of studies on biomarkers indicators of health or disease status to see if a knowledge of these can affect people's behaviour.
They learned that if you reveal factors like carbon monoxide levels in blood - increased by smoking it does encourage people to quit for fear they may be harming themselves. Other factors that are useful to know are whether you have high cholesterol or a genetic susceptibility to cancer. These were also found to lead to positive changes in behaviour.
However, the researchers point out that people need support to change their health behaviours. Doctors shouldn't just leave them with the bad news that they are poisoning themselves with carbon monoxide, for instance, for this could do as much psychological damage as the physical harm from smoking.