Cranberry flavoured 'Aspire' is said to burn off 209 calories within 3 hours of drinking it, according to scientists at Leeds Met University.
Apparently they found that when green tea was combined with caffeine, amino acid and ginger, there was a 'thermogenic effect'. This means the body generates more heat to digest food and temporarily stimulates the metabolism.
The drink is available from Holland & Barrett and is £1.59 and 12.5 calories a tin, but it is not advisable for those sensitive to caffeine to drink it.
Although more tests need to be carried out on this to confirm their findings, I think its well worth a shot over Christmas when we are all eating those extra calories.