In 2016, a researcher by the name of Ramsden at the NIH revisited data from the Minnesota Coronary Experiment. His team combed through hundreds of data from blood work and autopsies. Published in 2016 in the British Medical Journal, the study showed that the more cholesterol in a diet, the higher the likelihood of death. People who consumed the reduced fat diet had more deaths and this was seen especially in women and people age 65 and up.
Ramsden also dug out data from the Sydney Heart Study, which was similar to the Minnesota Coronary Experiment, but done in Australia. To see if results of lowering cholesterol on people with a different genetic makeup would be the same. The study found that the more you drop the fat, the higher your likelihood of death from cardiovascular disease in particular, and all causes in general.
But Ramsden didn't stop there, he looked at all studies of dietary interventions where saturated fat was replaced with vegetable oils, and did a meta-analysis. The studies included were the Minnesota Coronary Experiment, the Sydney Diet Heart Study, the LA Veterans Study, The Rose Corn Oil Trial, the Medical Research Council Soy Study, and others. All of these studies showed either no effect on cholesterol when saturated fat was replaced with vegetable oils, or worse, showed that you were better off being on the control diet. In the 1990s, Alessandro Menotti, an Italian counterpart of Ancel Keys in the Seven Countries Study, conducted a study on how many people had strokes or died from strokes 20 years after the study. Statistical analysis showed that only age and mean blood pressure carry significant positive coefficients. Whereas all the other available factors including serum cholesterol did not approach significant levels. So this analysis looked specifically at cholesterol and brain disease like strokes.
Another large study looking at dietary intake of fat and the risk of stroke involved a cohort of over 50,000 males, the US Healthcare Professional Study, aged 40 to 75 years of age. For this analysis, subjects were followed from 1986 to 2000. When they looked at the relationship between strokes and fat, they found nothing. Then they looked more closely to see whether the type of fat or the source of fat mattered. Again, there was no significance, meaning there was no relationship between red meat, high fat dairy products, nuts or eggs. And they also looked at the amount of consumption from less than once a week to more than once a day, none of it mattered.
Let's look at one final study. The Reasons for Geographic and Racial Differences in Stroke study, or the REGARDS study, is a national population-based longitudinal study out of the University of Alabama. This study observed 30,000 African-American, and Caucasian adults. The objective was to determine the causes for the excess stroke mortality in the Southeastern US, the Stroke Belt, and why there is such a disproportionate number of strokes among African-Americans. They looked at patterns in diet, and five emerged. Fast-food, southern, plant-based, sweets, and alcohol. The one pattern that was consistently associated with higher mortality in strokes was the southern diet. And the one that was the least likely to be associated with stroke and mortality was the plant-based diet.
The southern diet was high in fried food, processed meats, and sweetened beverages, and low in fruits and vegetables.
They even created multiple statistical models to try to adjust for the association of diet with other factors like age, race, sex, education, income, smoking, and being sedentary. With each model, the southern diet was statistically likely to be associated with strokes and mortality.
All this data caused the American Heart Association to change their longstanding recommendation of a low-fat diet to removing that recommendation altogether in 2015. The recommended amount of saturated fat remains at 10% or less however. We've now seen enough strong data to debunk the association between dietary fat and not only heart disease, but also brain disease in the form of strokes and overall mortality from these diseases. The pendulum swung in the other direction and mass media went from vilifying fat to glorifying it.