I feel like I've done them all and got no t-shirt, the worst for me was definitely the Dukan diet. I ate extra light philly on seaweed for days.... So confusing and so ridiculous, I realised when I tried to explain to hubby how good it was that it sounded insane! Would love to hear what other peoples worst diets have been. Btw i I know for some Dukan may be great, this is my experience only!