Meals at a restaurant on the UC San Diego campus. (File photo by Chris Stone/Times of San Diego)
Heart disease — affecting almost half of American adults — is the leading cause of death in the United States, claiming 700,000 lives each year.
As a practicing cardiologist for more than 20 years, I’ve watched patients do everything “by the book.” They eat according to the Dietary Guidelines for Americans — the federal government’s blueprint for nutrition policy — and still see their weight climb, blood pressure rise, and heart health deteriorate.
The problem isn’t their effort. It’s the guidance itself, which promotes high-carbohydrate, low-fat diets that can actually worsen metabolic health, which can in turn worsen heart disease. Many assume that by following the government’s recommendations they can improve their health — but, too often, the opposite is true.
With the next edition of the Dietary Guidelines scheduled for release this month, we have a critical opportunity to move beyond outdated orthodoxy and align federal nutrition policy with modern science and clinical experience. Done right, this update can turn back the tide of chronic illness and save lives.
Since 1980, the Departments of Agriculture and Health and Human Services have issued the Dietary Guidelines every five years. These recommendations shape not only personal choices but also the food in school cafeterias, military mess halls, hospitals and nursing homes. They inform SNAP and WIC benefits, nutrition education, and even the labels on grocery store shelves.
From the start, however, the guidelines steered Americans in the wrong direction. They marked a sharp departure from prior eating patterns by encouraging Americans to cut back on natural dietary fats and rely more heavily on refined high-carbohydrate foods. Saturated fat — and cholesterol by extension — were unjustly stigmatized, while bread, pasta and cereal became staples of the American diet.
The recommendations were not made with a metabolically vulnerable population in mind. For people already struggling with insulin resistance, obesity or diabetes, a high-carbohydrate diet frequently only compounds the problem by driving up insulin, promoting visceral fat storage around vital organs, and fueling a cycle of weight gain and chronic disease.
Four decades later, the guidelines remain out of step with science and with the health needs of the majority of Americans. They impose arbitrary caps on saturated fat, despite evidence showing no consistent link to higher rates of heart disease or mortality. They recommend dietary protein well below optimal levels for most populations. And they direct Americans to get 45-65% of their calories from carbohydrates — sidelining low-carb or ketogenic diet options proven to support weight loss, stabilize blood sugar, and reduce the risk factors that drive heart disease.
Americans are being pushed toward metabolically damaging eating patterns.
Today, 93% of Americans live with metabolic dysfunction — meaning their bodies struggle to convert food into energy efficiently. This breakdown in basic metabolic processes fuels the country’s epidemic of chronic disease. More than 75% of Americans are now overweight or obese. Heart disease mortality rates have increased from the 2010s to the 2020s, even as cholesterol levels have steadily fallen.
Put plainly: Federal nutrition policy has fallen far short of making Americans healthier. I know this to be true not only from statistics but from my own patients’ journeys. Many of them ate exactly as federal guidance prescribed and still found themselves gaining weight and developing hypertension, diabetes and heart disease. For years, I resisted the idea that fault could lie with the guidelines.
Like most physicians, I was trained to be wary of fat and to consider carbohydrates as the foundation of a healthy diet. I dismissed suggestions that a low-carb or ketogenic diet could improve cardiovascular outcomes.
But then I tried it myself — and my own weight, cardiovascular markers, and energy improved. When I cautiously introduced the approach to my patients, I saw transformations I couldn’t ignore: their insulin sensitivity, blood sugar levels and blood pressure began to improve. These changes struck at the true drivers of coronary heart disease — metabolic dysfunction, obesity and type 2 diabetes — all stronger predictors than cholesterol levels.
Their lives changed without a scalpel or a prescription. And their experiences mirrored what the science was increasingly showing: that the old low-fat, high-starch model had it backwards.
A review of randomized trials found that low-carbohydrate diets significantly improved weight, blood sugar and blood pressure — the very risk factors that drive heart disease.
Another analysis comparing different levels of carbohydrate restriction showed consistent benefits across degrees of reduction. And, in patients with type 2 diabetes, ketogenic approaches have dramatically lowered average blood sugar as measured by HbA1c — a long-term measure of glucose control — while delivering substantial weight loss, all changes known to reduce cardiovascular complications.
Yet our national guidelines remain stuck in an outdated paradigm.
The upcoming 2025-2030 Dietary Guidelines offers a chance to finally get it right — to align federal recommendations with the latest, most rigorous evidence. That means prioritizing whole foods, removing limits on saturated fats, optimizing protein intake, and including low-carbohydrate and ketogenic options for the metabolically vulnerable.
The nation’s leading killer isn’t inevitable. If the Dietary Guidelines are updated to reflect modern science, millions of Americans could soon be on the path to reclaiming their heart health.
Bret Scher, MD, is a board-certified cardiologist and lipidologist, and the founding medical director of the Coalition for Metabolic Health.
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