Despite what many people think, evidence of the ''badness'' of saturated fat is as strong as ever, University of Otago nutrition authority Jim Mann says.
Prof Mann was commenting on overseas research that says low fat recommendations of the 1970s and 1980s in the United States and the United Kingdom were not backed by sufficient supporting evidence.
He said it might be true of available evidence at the time of the recommendations, but since then the evidence against saturated fat had ''increased enormously''.
Published in the BMJ's Open Heart journal, the article is the latest in a string of research and scientific claims implying saturated fat might have been wrongly impugned as a dietary villain.
However, Prof Mann said the advice had not changed in that regard; people believing ''butter is fine'' had misinterpreted the research.
Because saturated fat had often been replaced with the wrong alternatives, such as sugar, some people now believed it was fine to return to the likes of butter.
''It is a very frustrating time because partial truths seem to have taken over and the core truths, the core messages, have been there for years and years.
''The badness of saturated fat has always been the core; the thing that has caused the confusion is the way that that was interpreted.''
He believed ''sanity will emerge'', but in the meantime it was highly confusing for the public.
''I believe that at the end of the day we'll get there, but we are going through a very frustrating time.
''People are moving back to butter because the science has been misinterpreted by people that for some reason have a vested interest, and I don't know why that has happened.''
Prof Mann suggests people consume the likes of olive and sunflower oil, chickpeas, lentils and wholegrain cereals.
He is writing an academic paper on how ''we got it all wrong'' in giving diet advice to the public.
However, a quick vox pop of shoppers in Dunedin yesterday revealed people largely ate what they believed best all along, and were not perturbed by the growing rift in scientific opinion.
Ministry of Health public health principal adviser Harriette Carr said ''the few'' recent studies endorsing high saturated fat diets did not counter the ''wealth of counter-evidence''.
''The Ministry of Health continues to recommend that New Zealanders lower their saturated fat intake and eat polyunsaturated fats instead. The vast majority of evidence from around the world supports this advice for population health.''
The ministry continually monitored findings from research, she said.
