The reasoning for this misleading claim is from a Tuesday Daily Mail article that stated, “Scientists have unscrambled the truth about eggs – eating the yolk is almost as bad as smoking for people at risk of heart disease…. But Dr David Spence revealed eating the yolk of an egg is about two-thirds as bad as smoking when it comes to the build up of plaques. Having surveyed 1,231 men and women, Dr Spence, of the University of Western Ontario, London, Canada, linked the findings to stroke and heart attack risk factors.”
The article was frightening, but luckily for the aforementioned brunch-goers and anyone who trains like Rocky, the study was mostly bullsh*t. According to the U.K.'s National Health Service, the results were skewed from the start. They were found by participants submitting in a questionnaire how many eggs they eat in a typical week. The responses were mostly estimates then, and they varied widely over time. There was also no way for the study to know how the eggs were prepared—if they were fried, scrambled, or boiled. This matters a lot to cardiovascular health.
Additionally, people who ate more egg yolks may be unhealthy in other aspects of their life. This wasn't taken into account:
People who ate more egg yolks may differ in other health and lifestyle factors from people who ate less, and this may account for their different artery build-up. For example, as the researchers rightly acknowledge, they did not thoroughly assess other dietary factors, exercise or waist circumference. It is possible that higher egg yolk consumption could be associated with less exercise and higher overall saturated fat intake – both well known risk factors for heart disease. The small changes in fatty build-up in the arteries seen with higher egg yolk consumption could have been accounted for by these other factors.
The NHS ultimately found that eating eggs in moderation was totally fine. So keep eating eggs, people. (Just not like Rocky. That's a recipe for salmonella.)