The so-called healthy diet may not be
Excerpt from the article: "The trial primarily attempted to influence activity levels and fruit and vegetable consumption, although it also reported on adiposity outcomes."
Perhaps the main reason intervention trials fail to achieve the desired result is because no attempt is made to correct the fatty acid profile of students' food intake. Moreover, the sort of dietary intervention likely to reduce weight gain in students is not likely to be approved by the National Health Service (NHS) Research Ethics Service Committee because NHS dietary advice is to limit saturated fat intake to prevent clogged arteries. (1)
Meanwhile, out in the real world, there's growing realization that the saturated fat/cholesterol hypothesis does not correspond with experience. For example: "Over the last 50 years, general nutritional wisdom has recommended a moderate consumption of fat. We have been told to dramatically lower our consumption of saturated fats (contained in butter, lard, milk, red meat, coconut oil…) and cholesterol (found in eggs, poultry, beef…). We have also been advised to increase our intake of polyunsaturated fats (contained in soybean, sunflower, corn, cottonseed oil…) and carbohydrates (found in pasta, bread, sugar…). But fat is a complex topic and these recommendations have been debated and questioned over the past 30 years. Some experts believe that these dietary recommendations – closely followed by the US population – are the main cause behind the country's high obesity levels and the rapidly growing number of people suffering from metabolic syndrome." (2)
In the United States a small mom and pop potato chip operation grew to a 10 million dollar business in less than a decade due to consumer enthusiasm for coconut oil and lack of competition from the rest of the snack food industry. Here is how they got started. "We soon realized that almost everything we had believed about fats was quite wrong. We realized that traditional, healthy fats that had been consumed for centuries (like cod liver oil, tallow, lard, coconut oil, and unpasteurized butter from grass-fed cows) were a source of essential nutrition. And that man-made vegetable oils are the product of an industrial manufacturing process that was invented 100 years ago were a source of real nutritional aggravation. As we embraced this healthy fat diet over the last decade, we came to use more saturated fat in more of our meals. And as our family grew to four children, we started experimenting with making everything they ate ‘fat friendly’. Perhaps, inevitably, we experimented with frying our own potato chips in coconut oil. (3)
The idea that saturated fats clog arteries has always been controversial as noted in this excerpt from a December 2012 article. " For almost 20 years, scientists have been arguing over whether Americans and others on a typical Western diet are eating too much of omega-6s, a class of essential fatty acids. Some experts, notably ones affiliated with the American Heart Association, credit our current intake of omega-6s with lowering the incidence of cardiovascular disease. Others, which include biochemists, say the relatively high intake of omega-6 is a reason for a slew of chronic illnesses in the Western world, including asthma, various cancers, neurological disorders and cardiovascular disease itself.(4)
Interestingly, T. Colin Campbell, the scientist who originated the phrase "plant-based diet", acknowledges that saturated fats are not a health hazard. In 2014 he wrote, "I propose that this argument for or against saturated fat should have been moot from the very beginning of this research. Here’s why. The original hypothesis that dietary fat, especially saturated fat, is chiefly responsible for heart disease began with laboratory studies over a century ago and the findings are, at best, uncertain.(5)
Primate obesity research suggests that the current dietary advice to limit fat intake is not helpful. For example, Barbara C. Hansen of the University of South Florida said calories, but not high fat, were important. “To suggest that humans and monkeys get fat because of a high-fat diet is not a good suggestion,” she said. Dr. Hansen, who has been doing research on obese monkeys for four decades, prefers animals that become naturally obese with age, just as many humans do. Fat Albert, one of her monkeys who she said was at one time the world’s heaviest rhesus, at 70 pounds, ate “nothing but an American Heart Association-recommended diet,” she said.(6)
It should be obvious by now that the anti-saturated fat campaign was a mistake. In a 1962 address delivered at Yale University, President John F Kennedy said, "For the great enemy of truth is very often not the lie -- deliberate, contrived and dishonest -- but the myth -- persistent, persuasive, and unrealistic. Too often we hold fast to the clichés of our forebears. We subject all facts to a prefabricated set of interpretations. We enjoy the comfort of opinion without the discomfort of thought."(7)
Among scientists who have questioned the saturated fat myth was S. L. Malhotra. In a 1967 British Heart Journal article he wrote, "Much evidence indicates that consumption of even small quantities of unsaturated fatty acids decreases the liability to ischaemic heart disease (Bronte-Stewart et al., 1956; Kinsell et al., 1952). This hypothesis, too, does not find support in our data. The South Indians eat largely seed oils containing as much as 45 per cent poly-unsaturated fatty acids, whereas ghee and other milk fats eaten by the Punjabis contain only 2 per cent polyunsaturated fatty acids...A survey of the incidence of acute myocardial infarction and the dietary behaviour in railway populations in India showed that the disease was 7 times more common among South Indians as compared with the Punjabis in the North, even though the fat intake of Punjabis was 8-19 times more than that of South Indians, and was chiefly of animal origin." (8)
More recently, in a May 2016 Times of India article, Neha Bhayana wrote, "Clarified butter remained India's culinary star for centuries till it was sidelined in the 1980s by vegetable oils because of its high saturated fat. The new oils were aggressively marketed as superior and heart-healthy. Of late, research has shown that saturated fats have no link to obesity, heart disease or early death."(9)
One wonders how much longer the anti-saturated fat campaign can persist given the fact that the whole narrative is built on a hypothesis that isn't validated by experience.
Competing interests: No competing interests