Government dietary guidelines are plain wrong: Avoid carbs, not fat

America is facing a chronic disease crisis. The federal government is fueling that crisis by promoting flawed nutritional advice that contradicts the latest research.

Every five years, the Departments of Agriculture and Health and Human Services publish the "Dietary Guidelines for Americans," which detail which foods Americans should eat or avoid. The highly influential document directs food labeling, school menus, public food programs, and government research grants.

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Researchers claim the guidelines are based on "the preponderance of current scientific and medical knowledge." Yet, since they were first introduced back in 1980, they've barely changed, even though a recent revolution in nutritional science has cast doubt on old assumptions.

Federal officials just started work on the 2020 edition. It is imperative that they take all the latest research into account. 

The guidelines' core message has always been that fats are bad and carbohydrates are good. The famous food pyramid, launched in 1992, made it clear that carb-loaded foods like pasta, cereal, and bread should comprise the foundation of one's diet. The government recommended that Americans eat up to 11 servings of grain per day. Fats — especially saturated fats — were to be consumed "sparingly."

The latest edition — released in 2015 — continues this theme. It recommends people eat relatively large servings of grains, including three to five servings of refined grains daily. And it lumps fats in with sugars as "empty calories." It advises Americans to limit their saturated fat intake to just 10 percent of daily calories — without presenting evidence to support this figure.

This guideline advice contradicts modern nutrition science which shows that fats, including saturated fats, aren't unhealthy. A dozen major literature reviews demonstrate that fat intake has little to no effect on death from cardiovascular disease.

Indeed, people who eat diets heavy in full-fat dairy products, including whole milk, experience lower rates of heart disease than people on low-fat diets, according to several reports, including a recent study published in the Lancet. Additionally, full-fat dairy has been associated with lower rates of obesity in children, teens, and adults.

Meanwhile, research shows carbohydrates are much worse than originally assumed. Excessive carb intake is linked to diabetes, cancer, and heart disease. One meta-analysis published in the British Journal of Nutrition comparing low-fat diets to low-carb ones concluded that weight loss is greater with a low-carb diet. 

At Indiana University Health, I oversaw research in conjunction with Virta Health that put patients with Type 2 diabetes on a low-carb diet that severely restricted grains and pasta while increasing their consumption of fatty foods such as avocados and butter. We didn't limit participants' daily calories. As long as they avoided carbs, they could eat to satiety. Health coaches worked with participants to help them adjust.

Our results were startling: A majority actually reversed their diabetes.

The key to eating healthy is avoiding carbs, not fat. Yet, the government's nutrition experts have ignored the latest research, and stuck to their anti-fat, pro-carb message.

Last year, at the request of Congress, the National Academies of Sciences, Engineering and Medicine conducted a detailed analysis of the guidelines' methodology and found it failed to meet basic standards of scientific rigor.

Even worse, the guidelines committee purposefully hid research on low-carb diets by burying it in the methodology section of its report, according to emails obtained through a Freedom of Information Act request. One of the report authors protested, "It's a large body of research . . . I don't think we should be putting it there," but was ignored. This is simply unacceptable.

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The guidelines are harming Americans, who have followed the government's anti-fat, pro-carb message. According to the Centers for Disease Control and Prevention, from 1971 to 2000, the percent of daily calories men consumed from saturated fat dropped from 14 percent to 10 percent. For women, it shrank from 13 to 11 percent. Meanwhile, men's consumption of calories from carbohydrates climbed from 42 percent to 49 percent, and women's consumption jumped 45 to 52 percent.

Since Americans have indeed followed the guidelines, we should have seen a drop in the rates of obesity, diabetes, and high blood pressure if the guidelines were scientifically sound— or at least rates should have stayed stable. Instead, they have skyrocketed.[1][2] 

Federal officials are forming the committee that will craft the 2020 edition of the Dietary Guidelines. This committee should include experts on evidence-based medicine instead of just nutrition. They're less likely to have been funded by the food industry or be pre-disposed to traditional dietary advice. Most importantly, they would not allow evidence to be dismissed, ignored, or hidden.

The guidelines are very influential. In fact, their pro-carb message is precisely why schools serve kids doughnuts and pop tarts for breakfast. Is this what we want for our children? We must ensure the next guidelines reflect the best thinking in nutritional science.

Sarah Hallberg is the medical director and founder of the Medically Supervised Weight Loss Program at Indiana University Health and an adjunct professor at Indiana University's School of Medicine.