For over 30 years, dietary fat has been seen as a major cause of heart attacks, strokes and cancer. This has been a health catastrophe. Ancel Keys's 'Seven Countries’ study, first published in 1970, brought about the widespread idea that we should all eat a low-fat, high-carb diet for optimal health. Had Keys used the entire data set covering 20 countries, his landmark paper would never have been published. The data did not support the hypothesis.
UCL’s Professor John Yudkin valiantly argued against this demonisation of fat based on bad science, citing his own experiments and data that showed excess consumption of refined carbohydrates to be the true culprit; he regrettably lost the ideological battle. Later, the late Dr. Robert Atkins was vilified as a pariah when he too questioned the anti-fat dogma.
Keys's conclusions led directly to the eventual adoption of the high-carb, low-fat diet endorsed by the American Heart Association and other institutions. The result has been an obesity epidemic.
The medical profession as a whole should hang their heads in shame at the way they formulated and promulgated nonsensical guidelines based not on science but on dogma, then blindly followed the status quo. For all their bleating about 'evidence-based medicine', most doctors seem to time-travel to the 1800s when it comes to nutrition.
One likes to think that Public Health advice is based on well-conducted studies and not one ‘expert' opinion. There are multiple kinds of studies; the gold standard to test the result of an intervention is a randomised controlled trial (RCT); a metaanalysis of RCT’s represents the highest level of evidence. An important, less robust level of evidence is long-term longitudinal studies (cohort or case series) where patients are tracked, sometimes for years with the outcome of interest observed. These studies often show correlation as opposed to causality, and need to be interpreted within context.
A new meta-analysis published in the BMJ Journal 'Open Heart' has revealed that the guidelines calling for low-fat, high-carbohydrate diets to be adopted for optimal cardiovascular health were never based on evidence. Supporters of the old paradigm ignored the 8-year, $500 million WHI study published in 2006 which showed no difference in cardiovascular mortality in women following a low-fat diet. They disregarded the meta-analysis published in 2010 which confirms no link whatsoever between intake of saturated fat and cardiovascular mortality. They brushed off the research published over the last 15 years all that lovely processed low-fat food is actually damaging to our vascular health. In 2014, a 14 year study was published indicating that consumption of high-fat dairy products appear to decrease the risk of diabetes. Study after study showing that fat is not the enemy has been sidelined.
Too many experts in the medical profession refuse to admit they got it wrong. Others thankfully are seeing the light. If only Dr. Atkins and Professor Yudkin had lived to observe their vindication.