Controversial UK cardiologist Aseem Malhotra has once again published an editorial disputing decades of research linking diets high in saturated fats with heart disease—much to the annoyance of health experts and researchers.

Malhotra, who maintains a high profile on media sites and television, has long advocated for high-fat diets, and he has blamed the rise of obesity and other health problems solely on sugar and processed foods. He has written scores of editorials and recently produced a documentary on the matter. Last year, Malhotra drew intense backlash from health experts after co-writing a report that encouraged people with type II diabetes and obesity to fight their diseases by eating more fat and ditching efforts to keep track of calories.

The report was written secretly and released by the National Obesity Forum, for which Malhotra was also a senior advisor. The Forum is funded by the meat industry and drug companies.

Like Malhotra’s past editorials, the report was widely criticized for cherry-picking data to dispute well-established associations and promoting the unfounded idea that eating more fat is beneficial for health. The same is true for the new editorial, which has made splashy international headlines this week.

The new opinion piece, published in the British Journal of Sports Medicine, was written by Malhotra and revised by two colleagues: Rita Redberg from the University of California at San Francisco and Pascal Meier from University College London. They claim that the idea that saturated fat can contribute to cardiovascular disease is “plain wrong.” Their claim largely hinges on a “landmark” 2015 review and meta-analysis of observational studies.

Critics took issue with this because observational studies can only establish correlations, not causation. Observational studies also have the trouble of including hidden biases.

“Indeed, one of the studies cited in the editorial noted the quality of evidence to be ‘very low,' indicating that the results are very uncertain,” noted David Nunan, a researcher at the Centre for Evidence Based Medicine at the University of Oxford.

Naveed Sattar, a metabolic medicine researcher at the University of Glasgow, went further on this point, calling the reliance on observational data “bizarre”:

Not only are such findings prone to many biases such that the results can often be incorrect, but more importantly plentiful randomized trial data—gold standard evidence—show lowered saturated fats lower cholesterol and risk of heart attacks.

For instance, in a large 2015 analysis of 15 randomized, controlled clinical trials, involving 59,000 people, researchers found that cutting back dietary saturated fat reduced the risk of cardiovascular events (including heart disease and strokes) by 17 percent.

Malhotra and his coauthors go on to make other, more minor points that researchers also disputed. These included the claim that “childhood trauma can lead to an average decrease in life expectancy of 20 years,” for which they don’t provide a reference. They also say that LDL, or “bad” cholesterol, is not a risk factor for heart disease.

“They could not be more wrong,” Sattar said, noting that plenty of randomized controlled studies directly contradict the assertion.

In the end, Malhotra and his coauthors suggest that people can protect themselves from cardiovascular disease with lifestyle changes such as increased exercise, eating “real food,” and following a Mediterranean diet. The last points muddle their message. They give no explanation of what “real food” is. And the Mediterranean diet discourages eating a lot of saturated fat, which undercuts their central argument that saturated fats are not harmful.

Overall, experts dubbed the editorial, like the ones before it, misleading and confusing.

“The Mediterranean diet and daily exercise can help reduce heart disease risk,” said Mike Knapton, associate medical director at the British Heart Foundation. “But I’m afraid the claims about saturated fat made in this opinion piece are unhelpful and misleading.”

As before, health experts recommend keeping saturated fats, added sugars, and sodium in check, while loading up on fruits, vegetables, lean meats and protein sources, low-fat dairy, and oils. But overall, people should focus on healthy eating patterns rather than individual foods or meals. In other words, there's no such thing as "good" or "bad" foods, just healthy or unhealthy diets. And everyone agrees that exercise is beneficial to health.

Christine Williams, a nutrition expert at the University of Reading, reflected on the authors' concern that it would be difficult to get across to people that "real food" and exercise are what's important:

The authors point out that "There is no business model or market to help spread this simple yet powerful intervention." Some would argue the journals have a very credible business model—based on attracting controversy in an area of great importance to public health where clarity, not confusion, is required.

British Journal of Sports Medicine, 2017. DOI: 10.1136/bjsports-2016-097285 (About DOIs).