Picture this: your grandparents ate their fried eggs without a second thought, your parents counted egg yolks the way others count cigarettes, and you, today, are discovering that all this caution was likely nothing more than overzealous advice. The egg, a symbol of simplicity and completeness, spent half a century under suspicion only to return, in the 21st century, to our plates with renewed legitimacy.

But how did a food that has been part of the human diet for millennia become public enemy number one for our arteries?

The Age of Fear: From the 1970s to 2000

It all began in post-war America. A physiologist named Ancel Keys put forward a seductive idea: if cardiovascular diseases were exploding, it must be because we consumed too much saturated fat and cholesterol. The equation seemed obvious: dietary cholesterol → blood cholesterol → arterial plaques → heart attacks.

This “lipid hypothesis” charmed institutions and the media alike. It didn’t matter that Keys himself had acknowledged an essential nuance: the cholesterol we eat doesn’t automatically translate into cholesterol in our blood, because the liver regulates its own production like a thermostat. Nor did it matter that his own experiments showed that most people respond only weakly to dietary cholesterol.

That nuance was lost in translation. His “Seven Countries Study” (1958–1970) appeared to support the theory, even though methodological flaws had been pointed out as early as 1957 by Berkeley statistician Jacob Yerushalmy. Then came the famous Framingham Heart Study, which was supposed to confirm the cholesterol–heart disease link. But in 1992, its director William Castelli admitted to an embarrassing finding: in Framingham, the more saturated fat and cholesterol people ate, the more their weight and serum cholesterol actually went down.

Despite such cracks, the dogma took hold. In 1977, the Dietary Goals for the United States recommended limiting eggs to no more than three per week. From then on, the egg became the embodiment of an invisible danger. Industry, sensing opportunity, flooded the market with cholesterol-free substitutes, pasteurized egg whites, and “light” products—often more expensive and less nourishing than the real thing.

Science Strikes Back: 2000–2025

The tide began to turn in the early 2000s. Large epidemiological cohorts in Japan, Finland, the U.S., and China started producing results. And the surprise was clear: no solid evidence condemned the egg.

In 2013, a Chinese team led by Ying Rong published in the British Medical Journal a meta-analysis pooling 17 prospective studies with more than 3.5 million person-years of follow-up. The verdict: no significant association between egg consumption and heart disease or stroke.

But the real turning point came in 2020. Jean-Philippe Drouin-Chartier of Harvard published the largest analysis ever conducted: three American cohorts totaling 215,618 people followed for over thirty years, plus a meta-analysis of 28 studies involving 1.7 million participants. The conclusion was crystal clear: eating up to one egg a day carries no cardiovascular risk.

That same year, the international PURE study, led by Mahshid Dehghan at McMaster University in Canada, added a new dimension. Following 177,000 people in 50 countries over nearly a decade, it showed that even in low- and middle-income countries, egg consumption had no negative effects—including in people with diabetes or existing heart disease.

Then came further confirmation. In 2021, Italian researcher Justyna Godos published a meta-analysis in the European Journal of Nutrition: eating up to six eggs per week was linked to a lower risk of cardiovascular disease compared to eating none at all. That same year, American cardiologist Chayakrit Krittanawong, writing in The American Journal of Medicine, concluded that even higher intakes—more than one egg a day—were not only safe but associated with a reduced risk of heart attack.

Unexpected Benefits

As the fear subsided, research began highlighting new advantages of eggs.

For the brain: Choline, abundant in egg yolks, is an essential nutrient. In 2018, Marie Caudill reported in The FASEB Journal that higher choline intake during pregnancy improved children’s cognitive performance in lasting ways. In 2022, Rima Obeid published a meta-analysis confirming that low maternal choline intake increased the risk of neural tube defects by 36%.

For vision: Egg yolks provide lutein and zeaxanthin, antioxidants that accumulate in the macula and protect against age-related macular degeneration. In 2017, a study showed that eating 12 eggs per week for a year greatly boosted blood levels of these carotenoids and improved vision in patients with early macular degeneration.

For metabolism: Egg proteins send powerful satiety signals to the brain, reducing appetite more effectively than a sugary breakfast. They also help regulate blood sugar by improving insulin sensitivity.

Caution and Nuance

Of course, the story is not entirely black and white. Some observational studies have suggested an increased risk among diabetics who consume a lot of eggs. But more reliable clinical trials are reassuring. In 2021, a study published in the Journal of Nutrition showed that adding two eggs a day to a plant-based diet had no negative impact on cardiovascular health in people at risk of diabetes.

Another nuance: about 15–25% of people are “hyper-responders,” meaning their blood cholesterol rises more sharply when they eat eggs. Yet this increase usually affects both LDL (“bad”) and HDL (“good”) cholesterol, preserving a favorable balance overall.

A Lesson in Common Sense

After being demonized and then rehabilitated, the egg today stands as a symbol. A symbol of how fragile nutritional science can turn into dogma. A symbol of the role of economic interests, which capitalized on fear to sell substitutes and medications.

But above all, the egg embodies a simple truth: nature sometimes creates foods so complete that industry cannot improve on them. Packed with high-quality protein, vitamins, choline, and carotenoids—affordable, versatile, and relatively sustainable—the egg deserves to reclaim its rightful place in a balanced diet.

And perhaps it also reminds us that, in the face of alarmist headlines and ever-changing diet fads, the best compass is a mix of science, culinary tradition, and plain old common sense.