Dean Ornish

Ornish is a physician at the University of California, San Francisco, and unlike most diet authors he has the trials. A randomised study published in the Lancet in 1990 showed measurable reversal of coronary artery blockage on a very low fat plant-based diet combined with exercise, stress management and group support, and Medicare eventually agreed to pay for the programme. Undo It! extends the claim to diabetes, prostate cancer and early Alzheimer's, where the evidence is a good deal thinner than for the heart. Critics point out that four components at once make it impossible to know which part does the work.