The mere thought of eating high-calorie food can boost your metabolism, according to research.

Scientists have claimed your metabolism speeds up when you believe you are eating something very indulgent and high in calories – regardless of how fattening it actually is.

Apparently, our metabolisms slow down when we we eat something our bodies believe to be low in calories.

Psychologist Alia Crum, at Columbia Business School in New York, conducted a ‘Milkshake Study’ to test this theory.

Dr Crum measured levels of the ‘hunger hormone’ – ghrelin – before and after a group of people drank a milkshake.

She gave each participant the same 380 calorie milkshake but half were labelled as containing 620 calories, while the other half were said to contain 140 calories.

Dr Crum discovered that people who drank the ‘high-calorie’ milkshake saw their ghrelin levels drop three times as quickly as those of the people who thought they were drinking low-calorie milkshakes.

The ghrelin hormone not only makes people feel hunger, it also influences the speed of metabolism.

The study suggested that it’s not just actual calorie consumption, but also perceived calorie consumption, that influences the body’s level of the hormone and, in turn, our metabolism rate.