The paradigm of a low-fat, high carb diet is becoming quite wobbly. Last June, Katherine Martinko @ Treehugger.com reviewed Nina Teicholz’s new book, The Big Fat Surprise: Why Butter, Meat & Cheese Belong in a Healthy Diet:
Over the ten years she spent researching her book, Teicholz interviewed top nutrition experts in the country, as well as many of the scientists who conducted the studies that remain the cornerstone of mainstream nutritional advice in the United States. She spent years reading the studies in their entirety, not just the abstracts. This effort paid off; she came across many inconsistencies, questionable methods, skewed data, and misleading conclusions. She interviewed people in the nutrition field who have been shunned for not “toeing the official line,” for daring to question whether minimizing saturated fat intake is really the best thing for human bodies.
The Big Fat Surprise reveals a world that is fraught with poor science, loads of industry money, political clout, and bloated egos pushing for specific results that always feature the demonization of fat, particularly saturated. It makes you realize quickly that the food pyramid, as we know it, has very little to do with what’s actually optimal for human health and far more to do with politics.
Now NewScientist (22 August 2015, paywall) carries an opinion piece to much the same effect, if somewhat more moderate. It’s by Dariush Mozaffarian, dean of the Friedman School of Nutrition Science & Policy, Tufts University, and David Ludwig, director of the New Balance Foundation Obesity Prevention Center:
… by 2000, growing research showed benefits from healthy fats, and harms in low-fat diets high in processed carbohydrates. So in 2005, US guidelines raised the upper fat limit to 35 per cent and, for the first time, set a lower limit of 20 per cent. Few people noticed, and the low-fat craze continued.
Through continued advances in nutrition science, it is now clear that an emphasis on reducing total fat is not only unhelpful, but can be harmful. Whether for weight loss or preventing long-term weight gain, diabetes, cardiovascular disease or cancer, evidence shows that it brings no clear health gain.
In contrast, meaningful health benefits are documented with high plant fat, Mediterranean-style diets supplemented with extra-virgin olive oil or nuts, in which total fat intake makes up more than 40 per cent of calories.
Based on these findings, the US Dietary Guidelines Advisory Committee omitted a total fat limit in recommendations, ahead of final benchmarks this year.
The US, UK and others should take note. Existing advice is driving consumers and industry towards low-fat products high in refined carbs, sugars and salt; and away from healthy higher-fat foods such as nuts, vegetable oils and whole-fat dairy products.
Note the divergence – Teicholz recommends animal fats, while Mozaffarian and Ludwig still recommend plant-derived fats. Martinko, the reviewer of Teicholz’s book, notes that
She [Teicholz] goes on to say that, if we returned to eating tallow and lard once again, it could free up much of the agricultural land currently dedicated to growing soybean, rapeseed, cottonseed, safflower, and corn oils.
Which sounds good at first. I do not know the current fate of tallow and lard – is it treated as waste, or used in another form? If the former, then maybe some agricultural land could be retired or repurposed; if it’s used in other applications, then I fear that more cattle would need to be raised for slaughter, which would utilize at least the repurposed land, and probably more.
Historically, concerns about saturated fat started with Dr. Ancel Keys, a Mayo and University of Minnesota researcher. From Wikipedia:
His interest in diet and cardio-vascular disease (CVD) was prompted, in part, by seemingly counter-intuitive data: American business executives, presumably among the best-fed persons, had high rates of heart disease, while in post-war Europe CVD rates had decreased sharply in the wake of reduced food supplies. Keys postulated a correlation between cholesterol levels and CVD and initiated a study of Minnesota businessmen (the first prospective study of CVD).[25] At a 1955 expert meeting at the World Health Organization in Geneva, Keys presented his diet-lipid-heart disease hypothesis with “his usual confidence and bluntness”.[26][27]
After observing in southern Italy the highest concentration of centenarians in the world, Keys hypothesized that a Mediterranean-style diet low in animal fat protected against heart disease and that a diet high in animal fats led to heart disease. The results of what later became known as the Seven Countries Study appeared to show that serum cholesterol was strongly related to coronary heart disease mortality both at the population and at the individual level.[28][29] As a result, in 1956 representatives of the American Heart Association appeared on television to inform people that a diet which included large amounts of butter, lard, eggs, and beef would lead to coronary heart disease. This resulted in the American government recommending that people adopt a low-fat diet in order to prevent heart disease.
I know that recently he was accused of cherry-picking his data. Dr. McDougall of the newsletter It’s The Food provides a defense of Keys here.
Interestingly enough, Keys was known for following his own advice (or, to reuse a more memorable phrase, eating his own dog food) and made it to the age of 100; his wife to the age of 97.
