If you want to lose weight, is a very low-fat plant-based diet the one to pick?

Dean Michael OrnishMD · internal medicine and cardiovascular disease; founder and president, Preventive Medicine Research Institute

A whole-foods plant-based pattern, low in fat and refined carbohydrate, is the pattern to build on.

What it rests onHis stated position, in his own printed reply: fruits, vegetables, whole grains, legumes and soy products in their natural unrefined form, low in fat, low in sugar and low in refined carbohydrate, with the gloss that 'It's the type of protein, fat and carbohydrates that matters.' His own trials measured angiographic stenosis, cardiac events, PSA and cognition rather than weight, so weight loss is not the endpoint he has tested and not the claim he makes.

Christopher D. GardnerPhD · nutrition scientist, Stanford Prevention Research Center

For weight loss in this population it finished third of four, and the lowest-carbohydrate arm won.

What it rests onA TO Z Weight Loss Study, JAMA 7 Mar 2007: 311 overweight and obese nondiabetic premenopausal women randomised to Atkins, Zone, LEARN or Ornish with weekly instruction for two months and ten months of follow-up. Twelve-month weight change: Atkins minus 4.7 kg (95% CI minus 6.3 to minus 3.1), LEARN minus 2.6 kg, Ornish minus 2.2 kg (95% CI minus 3.6 to minus 0.8), Zone minus 1.6 kg, with Atkins secondary metabolic outcomes comparable or more favourable. NIH funded. He has never withdrawn or reinterpreted the primary result, and his own later position is that the gap narrows when both arms are built well (gar-quality-over-macro).