New study below . Today's NY Times front-page story - .
The article is good, as far as it goes, but is misses some background.
So many bad things about dietary advice in the U.S. over the past 60 years can be traced back to Ancel Keys. 
I was amused to read in the 2nd paragraph of his Wiki page:
"The journalist Nina Teicholz, who directly disputes Keys’ theories in her book The Big Fat Surprise: Why Butter, Meat and Cheese Belong in a Healthy Diet (2014), writes that "...if there is a Great Man theory of history...whereby strong personalities steer events using their own personal charisma, in the history of nutrition Ancel Keys was, by far, the Greatest Man"." 
The Teicholz book  is an extraordinary work of scholarship as well as an enjoyable read. Keys would have hated his Wiki page.
Briefly, Keys had researched diet & cardiovascular disease in post-WWII Europe & come to the conclusion that cholesterol causes CVD. Which translated to animal meat causing heart disease. He published his flawed, but influential, "Seven Countries Study" at a time when there was concern in the U.S. about heart attacks. Why the concern? In 1955, President Eisenhower, age 64, suffered a heart attack while playing golf.
Keys appeared in Washington DC &, largely due to his personality, was responsible for the government setting aside a lot of money for research. Never mind that Ike had a four-pack-a-day habit, cholesterol must be to blame.
The money, of course, went to followers of Keys. It became a poor career move for a researcher to want to explore alternative theories. With few exceptions, cholesterol studies continued to be published for decades by followers of Keys & those who dared not question his dogma.
Two of Keys' men, mentioned in the new study, were Dr. Frederick J. Stare & D. Mark Hegsted:
"Dr. Frederick Stare (1910–2002) was the founder and first head of the Department of Nutrition at Harvard University’s School of Public Health. A lifelong fighter against the health food industry and the organic food movement, Dr. Stare often served as a government witness against natural-foods advocates, testifying that such proponents were alarmists and frauds. Over the course of his career, Dr. Stare procured massive amounts of funding for Harvard and his own research from food-manufacturing giants such as Coca-Cola, General Foods, and the National Soft Drinks Association." 
"David Mark Hegsted (March 25, 1914 – June 16, 2009) was an American nutritionist who studied the connections between food consumption and heart disease. His work included studies that showed that consumption of saturated fats led to increases in harmful cholesterol, leading to the development of dietary guidelines intended to help Americans achieve better health through improved food choices. After his death, researchers uncovered his connections to research funded by the sugar industry in which Hegsted played down connections between sugar consumption and heart disease, focusing on saturated fats as the culprit." 
An important figure in the saga was John Yudkin, who, safely in London, had no reason to fear Keys' influence:
"John Yudkin FRSC (8 August 1910 – 12 July 1995) was a British physiologist and nutritionist, and the founding Professor of the Department of Nutrition at Queen Elizabeth College, London." 
Yudkin was warning of sugar's role in CVD from the mid-1950's.
From the new paper:
"Early warning signals of the coronary heart disease (CHD) risk of sugar (sucrose) emerged in the 1950s. We examined Sugar Research Foundation (SRF) internal documents, historical reports, and statements relevant to early debates about the dietary causes of CHD and assembled findings chronologically into a narrative case study. The SRF sponsored its first CHD research project in 1965, a literature review published in the New England Journal of Medicine, which singled out fat and cholesterol as the dietary causes of CHD and downplayed evidence that sucrose consumption was also a risk factor. The SRF set the review’s objective, contributed articles for inclusion, and received drafts. The SRF’s funding and role was not disclosed. Together with other recent analyses of sugar industry documents, our findings suggest the industry sponsored a research program in the 1960s and 1970s that successfully cast doubt about the hazards of sucrose while promoting fat as the dietary culprit in CHD."
"In 1965, the SRF asked Fredrick Stare, chair of the Harvard University School of Public Health Nutrition Department to join its SAB as an ad hoc member. Stare was an expert in dietary causes of CHD and had been consulted by the NAS, National Heart Institute, and AHA, as well as by food companies and trade groups. Stare’s industry-favorable positions and financial ties would not be widely questioned until the 1970s."
"On July 1, 1965, the SRF’s Hickson visited D. Mark Hegsted, a faculty member of Stare’s department, after publication of articles in Annals of Internal Medicine in June 196526- 29 linking sucrose to CHD. The first 2 articles reported results from an epidemiological study suggesting that blood glucose levels were a better predictor of atherosclerosis than serum cholesterol level or hypertension. The third (p210) demonstrated that sucrose, more than starches, aggravated carbohydrate-induced hypertriglyceridemia and hypothesized that “perhaps fructose, a constituent of sucrose but not of starch, [was] the agent mainly responsible.” An accompanying editorial (p1330) argued that these findings corroborated Yudkin’s research and that if elevated serum triglyceride levels were a CHD risk factor, then “sucrose must be atherogenic.”
"On July 11, 1965, the New York Herald Tribune ran a full-page article on the Annals articles stating that new research “threatened to tie the whole business [of diet and heart disease] in a knot.” It explained that, while sugar’s association with atherosclerosis was once thought to be theoretical and supported by limited studies, the new research strengthened the case that sugar increased the risk of heart attacks."
"On July 13, 1965, 2 days after the Tribune article, the SRF’s executive committee approved Project 226, a literature review on “Carbohydrates and Cholesterol Metabolism” by Hegsted and Robert McGandy, overseen by Stare. The SRF initially offered $500 ($3800 in 2016 dollars) to Hegsted and $1000 ($7500 in 2016 dollars) to McGandy, “half to be paid when you start work on the project, and the remainder when you inform me that the article has been accepted for publication.” Eventually, the SRF would pay them $6500 ($48 900 in 2016 dollars) for “a review article of the several papers which find some special metabolic peril in sucrose and, in particular, fructose.”"
& so on.
I think it quite reasonable for the men to be paid for the article, although it might have been prudent to disclose that fact in the small print. Much has been made of the payments since the new paper came out, but these men were committed to the Keys cholesterol dogma. Stare might have written the article gratis. I don't believe that the payments show corruption.
But what it does show, & Nina Teicholz makes this very clear in her book, is how Keys & his men sacrificed intellectual honesty to defend his theories.
Stamler, who co-authored papers with Keys & Stare was interviewed by Teicholz:
"And Yudkin!" Stamler nearly bellowed to me. ... "I was part of shooting him down!"
Decades later, it is still very personal.
"Walter Willett, M.D., Dr.P.H. ... is an American physician and nutrition researcher. Currently, Willett is the Fredrick John Stare Professor of Epidemiology and Nutrition and the chair of the department of nutrition at Harvard School of Public Health. He is also a professor of medicine at Harvard Medical School." 
"Willett, who is one of the most frequently quoted academic sources on nutrition in the news media, appears to have crossed a Rubicon when he denounced Katherine Flegal, an epidemiologist at the US National Center for Health Statistics, for publishing a study that showed people who were overweight (but not obese) lived longer than those deemed normal weight. “This study is really a pile of rubbish, and no one should waste their time reading it,” he told National Public Radio." 
What does all this have to do with PCa?
I keep hearing views on diet, from men with PCa, that seem to parrot the party line as laid down by Keys in the 1950's. It's a line that has flourished because opponents in academia have been starved of funds. Earlier this year, my wife was advised by a doctor to stay away from red meat & animal fat. Doctor's don't learn much about nutrition in medical school, but you don't need to be a doctor to have been indoctrinated.
Dramatic changes in smoking habits have had a profound effect on U.S. cardiovascular disease in the past fifty years. If Keys were still alive, he might argue that he was responsible for the changes in CVD rates. But one thing is clear, the pre-PSA era PCa rate steadily increased during the Keys era. As men began to eat less red meat, the PCa incidence rate did not drop. & the rate of increase did not falter.
Conventional dietary advice is tainted. & the more the U.S. food pyramid is tweaked, the worse things become.