 In my video, Eggs vs. Cholesterol in atherosclerosis, I profiled a study showing that smoking more than a pack a day for 10 years is bad for your arteries, and combining egg eating and smoking is even worse, thus the effect of eggs and smoking appear to be additive. But egg yolks alone in non-smokers was associated with artery clogging, plaque buildup, nearly two-thirds as bad as smoking. This certainly ruffled some feathers. Yes, eggs are by far the number one source of cholesterol in the American diet, but letters to the editor like this one protested that dietary cholesterol may have very little impact on blood cholesterol levels, citing this study, published in 1971, performed on eight people. But if you look at dozens of studies all put together, covering hundreds of study subjects, we find that blood cholesterol concentration is clearly increased by added dietary cholesterol. Here's an extreme example just to illustrate a year in the life of a study subject on and off eggs. First, they take them off eggs, putting them on a cholesterol-free diet, and his cholesterol plummets within just three weeks. Then they give him lots of eggs, and he's back in trouble, and stays there until they take the eggs away and put them back on the cholesterol-free diet, and so on and so forth, turning his high blood cholesterol on and off like a light switch made out of eggs. Of course, the only reason we care about our cholesterol levels or how much plaque is building up inside our arteries is because we want to avoid the consequences, like a heart attack. So, do eggs increase our risk of cardiovascular disease or not? Here's the latest meta-analysis, the latest compilation of all the best studies on egg consumption and risk of heart disease, going back to 1930. When you put them all together, what do we find? Overall, those that ate the most eggs had a 19% increased risk of cardiovascular disease, a 68% increased risk of diabetes, and then once you get diabetes, an 85% increased risk of heart disease. And it didn't take much, less than a single egg a day was associated with a significantly increased risk of heart disease. Just over half an egg a day, an increased heart disease risk between 6 and 40% and the risk of diabetes, 29%. They conclude that they're finding support the American Heart Association Dietary Guidelines, which advise restricted egg consumption in adults for preventing cardiometabolic diseases, like diabetes, our seventh leading cause of death, and heart disease, killer number one.