With our diets, we rely on objective science to guide both official policymaking and our personal choices. Unfortunately, the ‘objective’ studies are surprisingly wrong in their conclusions.

“The Big Fat Surprise” Part III. Monday: An interview with author Nina Teicholz, noting that the decades-long claim that foods with fat are unhealthy has little basis in science. Tuesday: Science and common sense took a beating 40 years ago, as official nutritional policy converged around an “eat less fat” prescription. Today: Understanding the fatal flaws in the research that led Americans to cut back on animal foods in the mistaken belief it would lead to better health.

There is no doubt that Americans in general aren’t in the best of shape these days. Fully two-thirds of all adults are considered overweight or obese. Heart disease remains a prime cause of mortality, diabetes is becoming epidemic, and the list of drugs we’re consuming to combat a litany of ills is truly staggering.

Commentary:  The Big Fat Surprise: Part IIIMany of these health problems are, quite properly, traced to our less-than-ideal dietary choices, and there has been no shortage of advice on how to remedy that problem from government, from advocacy groups and from the legion of self-styled nutritional gurus online, on cable and in a slew of infomercials running pretty much 24-7.

But what of all those often conflicting dietary prescriptions and proscriptions? With significant majorities of Americans saying they’re concerned about what they eat, the safety of the food supply and the well-being of their families, why can’t we reverse these problems by eating healthier?

Author Nina Teicholz offers a concise explanation in her book: Because so much of the advice is wrong.

In the chapter recounting the emergence of the first USDA Dietary Guidelines, which made a low-fat diet our official national priority, she writes, “A political decision had yielded a new scientific truth.” Even though the low-fat diet had already been shown to increase — not decrease — the risk of heart disease, the official consensus some 40 years ago was that, “A prudent person should eat less fat. Politics had short-circuited the process, and an untested hypothesis was elevated as the reigning doctrine.”

And that, friends, is where America’s dietary understanding went off the rails.

The low-fat approach is all wrong, and not just because politics trumped science. From a nutritional perspective, it’s inaccurate, and from the standpoint of optimal well-being, it doesn’t work.

Each aspect is worth exploring.

What nutritional science actually reveals. Teicholz dissected one of the biggest and most costly studies attempting to “prove” the low-fat-heart disease connection, a $150 million effort in the early 1980s called the Lipid Research Clinic Coronary Primary Prevention Trial (LRC for short). Some 3,800 middle-aged men with high cholesterol levels were divided into two groups, one receiving a cholesterol-lowering drug, the other a placebo.

But here’s the unbelievable part: Both groups were given the same low-fat dietary advice: cut down on eggs and eat only lean meat and low-fat dairy.

And although the final results showed only a slight improvement in mortality among the drug-treatment group — Teicholz calculated that it was only 0.2 percent! — the study was hailed as “proof” that cutting back on fat reduces the risk of heart attacks.

If that’s not concerning enough, the study also noted that men whose cholesterol was successfully lowered — by the drug, not the diets — were twice as likely to die from suicide. Why? Possibly because cholesterol depletion in the brain may interfere with proper neurological functioning.

Enjoy those egg whites and nonfat yogurt, people. And good luck with the suicide thing.

The pursuit of well-being. As Teicholz documents, the low-fat diet was first aimed only at older men at high risk of heart disease, but by the 1980s had become the official advice for everyone, with strict cholesterol targets recommended for men, women and children, and a serious reduction not just on saturated fat n meat and dairy but all fat in all foods.

The results have been catastrophic, especially for women and children.

She writes, “A 1995 American Heart Association publication stated that Americans should control fat intake by increasing refined-carbohydrate consumption.” Quoting from the AHA pamphlet, “Choose snacks from other food groups, such as low-fat cookies, low-fat crackers, unsalted pretzels hard candy, sugar, syrup, honey, jam, jellies, marmalade.”

Is it any wonder we’ve become Obesity Nation?

Teicholz also skewers the impact of the Dean Ornish, super-low-fat, near-vegetarian diet — one of only two that are actually covered by Medicare, it should be noted. Ornish, a physician and president of the nonprofit Preventive Medicine Research Institute in California, still receives undue praise for what some have described as a “revolutionary” method of maintaining health.

Teicholz, however, points out that his diet was never scientifically examined until a 1998 study showed that drastically lowering fat intake (less than 10 percent of calories, according to Ornish) exacerbated other problems. And for children, who need the fat and cholesterol in their diets to support proper growth and development of nervous system tissues, it was particularly inappropriate for parents to insist on a low-fat diet.

For example: The Dietary Intervention Study in Children way back in 1987 place 300 children 7 to 10 years old with unusually high levels of LDL-cholesterol on a low-fat diet. The results showed that not only did the low-fat diet fail to significantly levels of lower LDL or triglycerides — the whole point of the study — but the kids ended up getting less than two-thirds of the recommended RDAs of calcium, zinc, vitamin E and the B vitamins. Fat reduction might have made some sense for adult males at risk of a heart attack, but it was wildly inappropriate for children.

“The results [of the study] clearly suggested that a low-fat diet presented no particular benefits,” Teicholz writes, “and one clear cost to children, since the diet appeared to pose a nutritional risk according to the targets set by the RDAs.”

Finally, another serious health risk, breast cancer, has also linked to high-fat diets. Decades ago, researchers had noted that although Japanese women have very low rates of breast cancer, as soon as they emigrate to the United States, the rates go up, corresponding to a parallel increase in dietary fat consumption. Sobering statistics, but only as a correlation, not cause-and-effect. Nonetheless, compelling information to motivate women’s dietary choices.

Only it’s not accurate. The Nurses’ Health Study, which tracked nearly 90,000 nurses’ health status over 14 years, found no evidence that reducing fat reduces the risk of cancer. In fact, as Teicholz points out, exactly the opposite is true.

“Saturated fat actually appeared protective [in the study],” she writes. “The more fat the nurses ate, particularly the more saturated fat they ate, the less likely they were to get breast cancer.”

Basically, none of the various attempts to demonstrate that restricting fat calories and minimizing the intake of saturated fat in meat, dairy and eggs succeeded in proving anything other than a low-fat diet increases one’s risks of negative health consequences, not the other way around.

How does that message get communicated? Tune in tomorrow. 

Tomorrow: The way forward. Given the depths of society’s demonization of red meat, how does industry catalyze a change in the national consciousness?

The opinions expressed in this commentary are solely those of Dan Murphy, a veteran food-industry journalist and commentator.