LONDON: Forget crosswords. If you really want to boost your brain power, eat dark chocolate, consume cold meat and have plenty of sex, if possible everyday.

A team of international researchers has carried out a study and found that while dark chocolate and plenty of cold meat for breakfast boost grey matter, sex keeps the brain fit in later life, the Daily Mail reported in London on Monday.

According to the study, those wishing to improve their mental ability should also avoid smoking cannabis, watching soap operas and hanging out with those who moan. Instead, cuddling a baby, cheating at homework, reading out loud and doing a business degree can boost their mind power.

The theories of the researchers are contained in the book Teach Yourself: Training Your Brain .

"What we eat and drink, how we learn at school and what type of moods we have are all crucial. People can make lifestyle choices that will constantly increase our cognitive capacity throughout our adult lives.

"Mix with people who make you laugh, have a good sense of humour or who share the same interests as you, and avoid people who whinge, whine and complain, as people who are negative will make you depressed," the book's author and one of the researchers, Terry Horne, was quoted as saying.

The book also contains mental exercises and radical thinking on how diet, the environment, stress and other aspects of modern life affect our mental capacity.