Mostofthemedicalprofessionalsgivecrashdietsthebadname,sayingtheyarenotnutritionallycompleteandhasyo-yoeffectonceit"sstopped.OxfordprofessorSusanJebbdecidestotestthediet"seffectivenessinhelpingobesevolunteerstolosesomeweightand,hopfully,makesomeillness,liketype2diabetes,reverse..