Good News Sudoku Fans - You Burn 90 Calories with the Sudoku Diet

dailymail.co.uk - Sitting in your favorite armchair doing a crossword or Sudoku does not sound like a particularly effective way to use up calories.

But if you are about to postpone that trip to the gym and turn to the Coffee Break section of your Daily Mail instead, you may be pleasantly surprised.

Tackling puzzles for an hour, it seems, can burn more calories than are contained in many biscuits.

That was the eyebrow-raising claim being made by mental agility experts yesterday in a bid to encourage more people to log on to their brain-training website.

Doing puzzles and quizzes burns an average of 90 calories every hour, they say - while a chocolate chip cookie contains an average 56 calories, a custard cream 57 calories and a jammy dodger 85 calories.

Researcher Tim Forrester, from cannyminds.com, explained: 'Our brains require 0.1 calories every minute simply to survive.

'When we do something challenging such as a puzzle or a quiz we can burn through 1.5 calories every minute.'

The brain is made up of millions of nerve cells called neurons which transmit messages to the body, he explained.

Neurons produce chemicals called neurotransmitters to relay their signals.

These neurons extract three-quarters of sugar glucose, available calories and a fifth of oxygen from the blood to create neurotransmitters.

So doing difficult crosswords or challenging Sudokus means your brain will crave more glucose and more calories too, added Mr Forrester.

This means that if you spent two hours doing puzzles, you would have used 180 calories - which is more than are contained in a creme egg (173) or a bag of Hula Hoops (175), and only slightly less than in a pint of beer (182).

A British Dietetic Association spokesman said: 'When thinking hard, the brain needs to get its energy from somewhere. It can get this energy from burning calories.

'The brain is like any other body part - if you are working it hard, it will need more calories to work well.'

But it is clearly not possible to think yourself thinner. This is because although the brain uses a lot of energy, it does not use fat to do so.

Unlike sugars, fat molecules cannot be broken down into glucose.

The amount of energy used by thinking is a very small percentage of the total energy used in the brain, which is constantly using energy to function, experts warn.

So if you want to lose weight, you will still need to exercise and eat healthily.

Last year it emerged that millions of people use Sudoku to improve their maths skills after being turned off the subject by dumbed-down teaching at school.

Many gave up after GCSE because lessons were too unchallenging, a study showed.

This 'lost' generation discovered an interest and ability in the subject through logic puzzles.

Although you do not need to be good at maths to do Sudoku, the grids demand logical thinking which underpins maths, added researchers at Reform think tank.