In the second leg of the trip, the group march 200 miles from Bristol to Cumbria. The first leg saw two of them quit, but now things are going to get even tougher.
Despite all the walking, they're still eating too much and haven't been losing weight, so they're given a strict new diet and have to walk more miles per day.
And as the walkers pass the halfway mark they get the chance to relax in Blackpool with a ride on Europe's biggest roller coaster. But can the ride cope with six morbidly obese people?
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