"Goggles that trick the wearer into thinking the plain snack in their hand is a chocolate cookie, or make biscuits appear larger..."

... research at the University of Tokyo.

In experiments, volunteers consumed nearly 10 percent less when the biscuits they were eating appeared 50 percent bigger.

They ate 15 percent more when cookies were manipulated to look two-thirds of their real size.

It's all in the mind.