The Real Story Behind Cholesterol, Fat, and Heart Disease

Does Dietary Cholesterol Cause High Blood Cholesterol?

We like to think of science as a fail-proof compass pointing us toward better health outcomes. And in many ways, it does. The scientific method (hypothesize, test, observe, refine) has given us life-saving medicines, surgical advances, and countless insights into how the body works.

But science is also a human process, and humans get it wrong. History is full of examples where “settled science” began to get squishy, revealing flaws in old theories that once felt unshakable. One of the clearest examples is the story of cholesterol, and the impacts of earlier works is tripping up millions of people.

The Birth of the “Cholesterol Myth”

The story begins in 1953 when physiologist Ancel Keys introduced what came to be known as the “lipid hypothesis.” His theory makes sense on the surface: eating cholesterol-containing foods raised blood cholesterol, which clogged arteries and led to heart disease. At a time when heart attacks were rising rapidly, this theory seemed to provide the missing link.

Keys became a central voice in shaping medical and public health opinion, and his hypothesis took hold. Within a few short years, saturated fat and cholesterol were villains to be avoided at all costs. This demonization of fat was not just a matter of medical debate, it became deeply embedded in public consciousness, reinforced by government recommendations, the food industry, and even the sugar industry, which funded research to deflect blame away from sugar and toward fat.

The narrative gained dramatic momentum after President Dwight Eisenhower suffered a heart attack in 1955. With the nation eager to find a cause, Keys presented data that appeared to show a neat, linear relationship between dietary fat and heart disease. His graph, which included just six countries, told a tidy story that Americans, worried about their president and their own health, were quick to accept.

What Keys did not highlight was that he had data from 22 countries. When the full dataset was later analyzed by independent researchers, the clean line dissolved into a pattern that looked more like randomness and the evidence did not prove what Keys claimed.

Despite this shaky foundation, Keys’ simplified version of the data became the basis for decades of dietary guidelines. Food manufacturers jumped on board, reformulating products to be “low fat” and / or “cholesterol-free,” often by removing natural fats and replacing them with sugar, refined carbohydrates, and processed oils. The belief that fat was dangerous and cholesterol was harmful was reinforced year after year, until it felt like an unquestionable truth.

The consequences have been profound. For years, we’ve followed advice to cut healthy fats from the diet, while unknowingly consuming more processed foods. During this same period, rates of obesity, diabetes, and heart disease have continued to climb. Today, the scientific consensus has shifted. A growing body of evidence shows that Keys’ lipid hypothesis was oversimplified at best and misleading at worst. Many researchers now acknowledge that the blanket avoidance of saturated fats, based on his theory, has contributed to serious health consequences that we are still grappling with.

Why Lowering Cholesterol Didn’t Solve the Problem

Despite decades of telling people to cut cholesterol, the rates of cardiovascular disease have not improved in proportion to the effort. What has increased are the deeper drivers of disease: insulin resistance, chronic inflammation, and oxidative stress. These factors damage blood vessels and compromise cholesterol, making it harmful, while dietary cholesterol itself plays a far less significant role.

The pharmaceutical industry has continued to perpetuate the myth. Statins have become some of the most prescribed medications in the world, worth billions each year. A look at the last few decades has revealed that governing boards keep lowering the threshold for what is considered a “safe” cholesterol number, which seemingly only creates more candidates for medication while doing nothing to support the underlying cause.

Will the Real Cholesterol Please Step Up?

Cholesterol is essential for life with many physiological functions. Every cell in the body requires cholesterol to maintain structure, flexibility, and protection. The brain contains about 25 percent of the body’s cholesterol, where it supports memory, learning, and nerve function. Cholesterol is also the raw material for hormones like estrogen, testosterone, and cortisol, all of which are crucial for reproduction, energy balance, and stress response.

Without cholesterol, the body cannot make vitamin D, which regulates calcium metabolism and immunity. It is also required for bile production, which allows us to digest fats and absorb fat-soluble vitamins. The body considers cholesterol so important that it manufactures it itself and is a component of breast milk.

What Really Impacts Cholesterol Balance

Instead of fearing cholesterol in foods, the better question is what disrupts cholesterol metabolism in the first place. The main culprits are blood sugar imbalances and insulin resistance, chronic inflammation from sugar, processed foods, individual food sensitivities, and oxidative stress from poor quality oils, toxins, and pollutants. When these factors run amuck, cholesterol particles can become small and dense, contributing to poor health. But that is not a cholesterol problem, it's how the body is reacting to what it’s being fed and our individual health status.

The best way to support cholesterol balance is by returning to whole, nutrient-dense foods and avoiding the processed replacements that became popular during the low-fat era. That means choosing healthy fats like grass-fed butter or ghee, cold-pressed olive oil, coconut oil, avocados, and wild-caught fish. Nuts and seeds and full-fat dairy and eggs from grass-fed sources can also provide support (as tolerated). Meals that stabilize blood sugar, rather than causing spikes and crashes, reduce the insulin resistance that contributes to dysfunctional cholesterol.

For decades, the Mediterranean diet has been shown to support cardiovascular health, not because it is low in fat, but because it emphasizes unprocessed foods, leafy greens, vegetables, nuts, seeds, fish, and high-quality fats. This pattern reduces inflammation, provides antioxidants, and nourishes the body in the way it was designed to be nourished.

A Functional Nutrition Perspective

When I work with clients on cholesterol, my goal is not to chase numbers on a lab report alone. Instead, the focus is on uncovering the root causes of imbalance. By addressing these factors, not only does cholesterol naturally rebalance, but other markers of health like blood pressure, energy, hormones, and mental clarity also improve.