Some media coverage has suggested that there is a link between eating junk food and the rise of conditions like Crohn's disease and ulcerative colitis which involve inflammation of the digestive system. Mark Porter questions the evidence. As school's out for summer Mark finds out why teachers' voices need a rest. He also examines whether cholesterol lowering spreads and drinks do what they suggest. Also in the programme: is frying with olive oil harmful or the healthy choice?