A recent research published by cannyminds. com, and undertaken in association with mental agility expert Tim Forrester, has claimed that mental exercises like crosswords and sudoku puzzles can burn up-to 90 calories per hour, which are much more than calories in a single chocolate chip cookie (56).
Exercising one's brain for an hour can also burn more calories than those contained in jammy dodger (85), a custard cream (57) or HobNob (79). According to the study, giving the brain a thorough workout dramatically increases the calories burnt by the body.