Optimism can make you overweight
Dr Martin Hagger, a health psychologist at the University of Nottingham and Curtin University, Australia, said personalities are a result of both genes and the environment.
"Knowing you fall into one specific camp doesn't immediately mean you're going to develop heart disease, for instance, but it should wake you up to the risk and, as a result, give you the opportunity to recognise and target the less healthy aspects of your character -- such as smoking or drinking," the Daily Mail quoted him as saying.
Researchers from Doshisha University in Kyoto, Japan, and other centres, assessed obese men and women undergoing a six-month weight-loss programme involving counselling, nutrition and exercise.
The researchers found that those who were most positive lost the least weight. It's thought that looking on the bright side led to patients not caring about their weight problem and always giving into temptation.