The Diet goggles convince their wearers their stomach is full

The goggles can fool people eating a savoury snack into thinking they are actually eating a tasty
chocolate.

Professor Michitaka Hirose demonstrating the the diet goggles.

Researchers at the University of Tokyo say the illusion tricks a person's brain into thinking they are about to eat super-sized portions, while the wearer's hand remains normal size.
Volunteers wearing the augmented reality device were told to eat biscuits until they felt full to test the effectiveness of the goggles.

'By changing the size of the food and scaling it up we have shown that participants eat about 10 per cent less over the course of a day,' said Takuji Narumi, an assistant professor working on the project.
'This is because the brain believes visual information rather than the information it receives from the stomach or our other internal sensors.'