I make no claim to expertise or even competence in the area of nutrition. And yet, like all of us, I have noticed with alarm that Americans are among the most obese people in the world. It is a dubious achievement, indeed.
How did we get to this point?
The reason, Nina Teicholz explains in the Wall Street Journal this morning, is counterintuitive. We are getting fatter because we refuse to eat fatty foods. Americans have become obese by following government dietary guidelines:
Seeing the U.S. population grow sicker and fatter while adhering to official dietary guidelines has put nutrition authorities in an awkward position. Recently, the response of many researchers has been to blame "Big Food" for bombarding Americans with sugar-laden products. No doubt these are bad for us, but it is also fair to say that the food industry has simply been responding to the dietary guidelines issued by the AHA and USDA, which have encouraged high-carbohydrate diets and until quite recently said next to nothing about the need to limit sugar.
It seems logical that eating fatty foods makes us fat. The truth, however, is that replacing fatty foods, like steak and butter, with carbohydrates and vegetable oils makes us fatter. Moreover, following the government’s diet will not only make us fat; it’s bad for our health.
Teicholz describes some of the unintended consequences of the war on fatty foods:
One consequence is that in cutting back on fats, we are now eating a lot more carbohydrates—at least 25% more since the early 1970s. Consumption of saturated fat, meanwhile, has dropped by 11%, according to the best available government data. Translation: Instead of meat, eggs and cheese, we're eating more pasta, grains, fruit and starchy vegetables such as potatoes. Even seemingly healthy low-fat foods, such as yogurt, are stealth carb-delivery systems, since removing the fat often requires the addition of fillers to make up for lost texture—and these are usually carbohydrate-based.
The problem is that carbohydrates break down into glucose, which causes the body to release insulin—a hormone that is fantastically efficient at storing fat. Meanwhile, fructose, the main sugar in fruit, causes the liver to generate triglycerides and other lipids in the blood that are altogether bad news. Excessive carbohydrates lead not only to obesity but also, over time, to Type 2 diabetes and, very likely, heart disease.
The strange truth is:
Too much whole-grain oatmeal for breakfast and whole-grain pasta for dinner, with fruit snacks in between, add up to a less healthy diet than one of eggs and bacon, followed by fish. The reality is that fat doesn't make you fat or diabetic. Scientific investigations going back to the 1950s suggest that actually, carbs do.
Naturally, we all believe that butter is bad and that vegetable oils are good. Again, this is far from the truth:
In those early clinical trials, people on diets high in vegetable oil were found to suffer higher rates not only of cancer but also of gallstones. And, strikingly, they were more likely to die from violent accidents and suicides. Alarmed by these findings, the National Institutes of Health convened researchers several times in the early 1980s to try to explain these "side effects," but they couldn't. (Experts now speculate that certain psychological problems might be related to changes in brain chemistry caused by diet, such as fatty-acid imbalances or the depletion of cholesterol.)
I had not known it, but I am intrigued by the possibility that psychological problems might be caused by a cholesterol-deficient diet.
One recalls that New York’s former mayor Michael Bloomberg declared war on transfats. On this score the science is far from settled. Vegetable oils, the ones that are used in place of transfats, produce their own problems:
We've also known since the 1940s that when heated, vegetable oils create oxidation products that, in experiments on animals, lead to cirrhosis of the liver and early death. For these reasons, some midcentury chemists warned against the consumption of these oils, but their concerns were allayed by a chemical fix: Oils could be rendered more stable through a process called hydrogenation, which used a catalyst to turn them from oils into solids.
Yet paradoxically, the drive to get rid of trans fats has led some restaurants and food manufacturers to return to using regular liquid oils—with the same long-standing oxidation problems. These dangers are especially acute in restaurant fryers, where the oils are heated to high temperatures over long periods.
The past decade of research on these oxidation products has produced a sizable body of evidence showing their dramatic inflammatory and oxidative effects, which implicates them in heart disease and other illnesses such as Alzheimer's. Other newly discovered potential toxins in vegetable oils, called monochloropropane diols and glycidol esters, are now causing concern among health authorities in Europe.
Regrettably, women have been the victims of the crusade against saturated fat. First, because the studies were all performed on men. Second, because women under fifty are not at risk for heart disease. Third, because higher cholesterol levels in women are better for their health:
Cutting back on saturated fat has had especially harmful consequences for women, who, due to hormonal differences, contract heart disease later in life and in a way that is distinct from men. If anything, high total cholesterol levels in women over 50 were found early on to be associated with longer life….
Since women under 50 rarely get heart disease, the implication is that women of all ages have been worrying about their cholesterol levels needlessly. Yet the Framingham study's findings on women were omitted from the study's conclusions. And less than a decade later, government health officials pushed their advice about fat and cholesterol on all Americans over age 2—based exclusively on data from middle-aged men.
Sticking to these guidelines has meant ignoring growing evidence that women on diets low in saturated fat actually increase their risk of having a heart attack. The "good" HDL cholesterol drops precipitously for women on this diet (it drops for men too, but less so). The sad irony is that women have been especially rigorous about ramping up on their fruits, vegetables and grains, but they now suffer from higher obesity rates than men, and their death rates from heart disease have reached parity.
Perhaps it’s time for the government to get out of the nutrition business. It’s one thing for someone like me to be uninformed on the matter. It’s quite another for a government agency to be misinformed and to promote misinformation as truth.