looking for a fast diet? there s one that s taking britain by storm. it s a diet which you fast for two days a week and then you can feast. abc s juju chang set out to see if it works. reporter: maybe it s the stiff upper lip, but it seems much of england is obsessed with fasting. not every day, just two days a week. please, could i have the almond croissant. reporter: the other five days, you can eat whatever you want. it s called the fast diet. according to the creator, tons of britons are losing tons of weight. i step on the scales each week, the pounds are dropping offer. reporter: tara mclaughlin says she lost 36 pounds over seven months. the two fasting days allow just 25% of a normal adult s intake, 500 calories for women, 600 for a man. the british fasting craze is the brainchild of dr. michael mosley. he met with american researchers