Eggs Aren’t the Enemy: The Truth About Cholesterol, Saturated Fat, and Choline
EGGS — CHOLESTEROL + HEART HEALTH + FERTILITY
Eggs Aren’t the Enemy: The Truth About Cholesterol, Saturated Fat, and Choline
Eggs have been unfairly demonized for decades — from “cholesterol will clog your arteries” to fears over homocysteine and TMAO. Here’s what human biology and modern research actually show, why dietary guidelines reversed course, and how eggs fit into a nutrient-dense, whole-food diet.
Author
Craig McCloskey
Board-Certified Nutritionist
For decades, eggs have been one of the most controversial foods in nutrition. One day they’re a “perfect protein,” the next they’re framed as a cardiovascular disaster waiting to happen. We’ve been told to fear the yolk because of cholesterol, to avoid the fat because it “clogs arteries,” and to worry about obscure compounds like homocysteine and TMAO as if eating eggs were a metabolic landmine.
But when you slow down and actually examine the science - not headlines, not fear-based soundbites - the case against eggs quickly falls apart.
In fact, eggs may be one of the most nutrient-dense, evolutionarily appropriate foods humans have ever consumed.
Let’s walk through the major claims against eggs, where they came from, and what the research actually shows.
The Cholesterol Myth: Where It Started - and Why It Failed
One large egg yolk contains roughly 200 milligrams of dietary cholesterol. That number alone has scared people away from eggs for decades. The assumption was simple: eat cholesterol, raise blood cholesterol, clog arteries, increase heart disease risk.
It sounds logical on the surface. In the early 1900s, autopsies of people who died from heart attacks revealed cholesterol-rich plaques in their arteries. Researchers at the time assumed that dietary cholesterol from foods like eggs, butter, meat, and dairy was directly responsible.
I.e., Eat dietary cholesterol = cholesterol in arteries.
But human physiology doesn’t work that way.
Your body tightly regulates cholesterol production because cholesterol is essential. It’s a structural component of virtually every cell membrane, a precursor to steroid hormones, vitamin D, bile acids, and plays a crucial role in brain and nervous system function. When you eat more cholesterol, your body simply produces less. When you eat less, your body produces more.
The result? For most participants, blood cholesterol barely changed. In some cases, it actually went down.
Over the next several decades, this finding was replicated again and again.
Unfortunately, in 1980, the first-ever Dietary Guidelines for Americans came out and it recommended that people “avoid too much fat, saturated fat, and cholesterol”.
From there, virtually every box, package, and bag of food has labels slapped on it - “cholesterol free”, “low fat”, and “fat free”…
The damage had already been done, and the belief that eating dietary cholesterol clogs arteries had been ingrained in American culture.
This led nearly every country to remove any upper limits on dietary cholesterol intake. Dietary cholesterol, it appeared, had finally been vindicated.
Yet, it took the United States until 2015 to remove any upper limits on dietary cholesterol. More than two decades after science had definitely proved that eating dietary cholesterol isn’t problematic for the overwhelming majority of humans.
And they did it every so quietly in the middle of the 2015 - 2020 Dietary Guidelines, stating that “dietary cholesterol is no longer a nutrient of concern for overconsumption.”
No major announcement. No headlines. Nothing.
And the worst part? To this day, the FDA still allows food labels to say “cholesterol-free,” keeping the fear alive long after the science moved on.
This still gives the perception to the average person that eating cholesterol should still be avoided.
But things are changing. The brand new 2025 - 2030 Dietary Guidelines for Americans have officially declared eggs as a health food that should be eaten generously.
Watch the Full Breakdown
If you want a deeper dive into the science behind eggs, cholesterol, saturated fat, homocysteine, TMAO, and how these topics are often misrepresented, I break it all down in the full video below.
Read the full transcript
Stop eating eggs. There's only two things wrong with the egg. The yolk and the white. One egg yolk has over 200 mg of dietary cholesterol. That's the equivalent of two Burger King Whoppers with cheese. Think about that. Eating dietary cholesterol from animal richch foods has never once been shown to be problematic for humans. We actually did an entire breakdown on this topic in this video right here. But just to give you a quick recap, in the early 1900s, when heart disease was becoming increasingly more prevalent, autopsies found cholesterol plaque buildups inside of the arteries of people that were dying from heart attacks. So, they quickly made the association that if you eat cholesterol-rich foods like butter, meats, egg yolks, and dairy, then that's the same cholesterol that will just get clogged up in your arteries. It kind of makes logical sense just from a visual perspective. But biochemistry, our human bodies don't work that way because the more that this topic was studied over the past 120 years, we actually found the opposite to be true. The more you ate these animal richch foods in the context of a healthy whole food diet, you lived healthier. You didn't develop plaques inside your arteries. Even Anel Keys himself, the founder and leader of the diet heart hypothesis, tested this theory in 1952 with a study where he fed participants, human participants, upwards of 3,000 mg of dietary cholesterol every single day for months. And he found that it made no difference on their total blood cholesterol numbers. This was the equivalent of eating 15 eggs per day. And even some of the participants, their total cholesterol went down. However, saturated animal fats and dietary cholesterol kind of got all lumped together. And then over the course of the next 50 to 60 years, we started putting regulations on dietary cholesterol altogether. So, in the 1980s, the American Heart Association, the FDA started cracking down and listing a lot of foods as cholesterol free, lowfat, fat-ree, and low cholesterol. And just as a quick side note, right around this time in the 1980s is right around the same time that we saw the obesity epidemic skyrocket. Alzheimer's became more prevalent and type 2 diabetes explode. But in 1992 is when everything changed. This is when the largest study ever conducted on this subject found that for the overwhelming vast majority of humans, dietary cholesterol from things like red meat, egg yolks, butter, and other animal foods have minimal to no impact on humans blood cholesterol numbers. Meaning that you can eat as much cholesterol as you want and it's really not going to make a difference on your own blood cholesterol. So every country followed suit over the next 10 to 15 years and removed any upper limit on dietary cholesterol. They said you could eat as much as cholesterol as you wanted. It's not going to make a difference. But it took the United States dietary guidelines until 2015 to remove their stance on dietary cholesterol by quietly saying quote dietary cholesterol is no longer a nutrient of concern for overconumption. However, today the FDA still allows products to be labeled as cholesterol-free or low cholesterol, fat- free or low fat, giving us the consumers that cholesterol is still a problematic nutrient for humans. So, you don't need to worry about eating dietary cholesterol. And in fact, eating egg yolks that's rich in cholesterol can be a perfectly healthy food. When it comes to the egg white, the egg white is loaded with all kinds of problematic, insidiously destructive types of proteins. Specifically, some of the essential amino acids like methionine that at excessive levels gets converted into homocyine that actually promotes inflammation specifically in our arteries promoting heart disease. This is pretty misguided. Let's break this down in 2 minutes. He's saying that if you eat methionine, which is an amino acid that we need in our diet, it's an essential nutrient. Our bodies can't make it, so we need to get it in our diets each day. He's saying that if you eat more methionine that it's going to turn into this compound called homocyine. And this is somewhat true. When you have higher levels of homocyine in your lipid panels, then you're going to be more at risk for cardiovascular diseases. But the misguided thing about this is just eating more egg yolks and eggs in general won't lead to higher homocyine levels. There's a major caveat that he left out in this video. When you're eating enough complimentary nutrients like B vitamins, folate, vitamin B12, riboplavin, then you keep your homocyine levels in check. These B vitamins help to regulate homocyine inside your body. There's a ton of high-quality science showing that if you're eating B vitamins every day, then your homocyine levels will be in a healthy range. This study here found that the treatment of high homocyine with it says folic acid, but it should be folate. Folic acid is the synthetic version, but with folate and B vitamins prevents the development of atherosclerosis, cardiovascular disease, and strokes. Don't be worried about eating too much methionine from eggs. Your body needs it. It's an essential amino acid, and as long as you're eating an otherwise healthy whole food-based diet. You don't need to worry about high homoyine levels. Now, when it comes to fat, the egg is 67% fat. Of that fat, 20% is coming from saturated fat. And that saturated fat raises cholesterol levels. It actually clogs arteries. And then lastly, it promotes insulin resistance. This belief that saturated fat clogs arteries has been thoroughly debunked many times over. We've actually done several videos dedicated to this topic on our channel alone. Since 2009, there have been 16 reviews of hundreds of randomized control trials looking at saturated fat and cardiovascular disease. And all of them have shown conclusively that saturated fat doesn't contribute to cardiovascular disease. And why would it? We have been eating animal- richch foods for millennia, pretty much since humans have existed. And why would something that gives us so many essential nutrients, nutrients that we can only get from animal foods, why would that contribute to heart disease? It doesn't make sense. But when you look at lowquality observational data that can only show associations, this isn't highquality randomized control trials that can show cause and effect. When you are looking at observational studies that show an association, it looks like that the saturated fat, the eggs are associated with heart disease. Because how are eggs typically eaten in our society today? They're usually eaten with a bagel, which is refined grains, added sugars, seed oils, and other ultrarocessed foods. Is it the eggs that are causing the heart disease or is it all the other junk food and unhealthy lifestyle factors that now come along with the eggs? However, there's a lot of highquality scientific evidence that shows when you eat eggs as a part of a healthy whole foodbased diet, it actually improves lipid profiles like total cholesterol, the healthy types of LDL, HDL, triglycerides, and insulin resistance. So, don't be worried about the types of fats in egg yolks. They're actually very healthy. They're going to help with brain health, immune function, fertility, pregnancy, and so much more. Ael, it is high in a substance called choline. It's one of the highest in the animal kingdom in choline, 150 mg per egg yolk. And that choline gets converted by our guts and our liver enzymes into a hellish substance called TMAO, trimethylamine oxide, that promotes heart disease like no other. So for all these reasons, the saturated fat, the dietary cholesterol, the TMAO, and the homocyine, I recommend you finding a different breakfast, namely oatmeal. Choline is one of the most essential nutrients that we need to get from our food if we want to have a healthy brain and mood, optimal fertility and pregnancy, healthy hormones, cell structure, and nervous system regulation among many other things. Simply put, if you are not getting enough choline in your diet, then you are going to be setting yourself up for many pretty serious health issues. I actually just interviewed Lily Nichols RDN on our platform, and she had a lot to say about how important choline is for fertility and pregnancy. It's one of the most important nutrients that you can get, just not as a mother, but also as a father contributing to the health of your soon to be child. Choline is super, super important. and she shared with me that over 94% of women in the United States are currently deficient or getting on the lower end of choline in their diets every single day. And that number jumped up if you weren't consuming eggs each day. Just as a general range, American adults need somewhere around the range of about 500 mg of choline each day, which you can get just from a few egg yolks. And pregnant women need over twice that amount, coming in at about 900, maybe even 1,000 milligs. Some research has shown pregnant women need even more than that. So to suggest that we should limit our egg yolk consumption because it contains choline simply because it's going to raise TMAO levels is really misguided. TMAO or trimethylene and oxide is a byproduct of digesting certain nutrients like choline and carnitine in the diet. And it's very important to note that just like saturated fat, there is no highquality randomized control data in humans suggesting that TMAO causes heart disease in humans. TMAO has only been associated at high levels with cardiovascular disease and chronic kidney disease. But as we just addressed, association is not the same as causation. Most of the research showing that TMAO is linked to cardiovascular disease or chronic kidney disease comes from mice or observational data in humans. There is no mechanistic data that I have found. If you found some, please send it to me in humans that shows that TMAO is causal in any way, shape or form of cardiovascular disease or chronic kidney disease in humans. The last thing, and this is pretty important to note, is that fish, eating fish like salmon, sardines, and all the healthy types of fish, the Mediterranean diet, right? All these fish have the highest sources of pre-formed TMAO in them. And eating a lot of fish has only been shown to be heart-healthy. People who eat a lot of fish have a healthy heart, mostly due to a lot of the omega-3 rich content in there. But if TMAO was that problematic for humans, wouldn't eating a lot of fish be shown to be causal or even associated with heart disease or chronic kidney disease? Instead, it's been shown to be the opposite. So, how can TMAO be causal for a lot of these issues when it's not problematic in fish when it's the highest source of TMAO? There's a lot more we need to learn about some of these substances like TMAO, but really just reeling it back in. Eating foods that humans have been eating the longest and have a great track record with that also has a lot of bioavailable nutrients is one of the best things that you can do. Just continue to eat the foods that humans have been eating the longest. Go source your foods locally from a local farm. Don't fear animal foods that we've been eating for millennia. And eggs in particular are a treasure trove of nutrients including lutein and zeazanthin. These are antioxidant molecules that are in high amounts in that dark orange yolk that are going to help with your vision. Antioxidants help you by staying young, help your skin, your hair, your nails. It's also full of bioavailable protein that's going to be more absorbable than many plant proteins. And like I mentioned, it's also full of choline and it's full of fats soluble vitamins like vitamins's A in the retinol form. D3 is the most bioavailable form of vitamin D, vitamin E, and vitamin K2. And it's also rich in essential fatty acids. Egg yolks are essentially nature's perfect health food. Just like beef liver, these are basically nature's multivitamins. If you can eat more egg yolks as a part of a healthy whole foods diet, you have nothing to worry about when it comes to any of these things that I just addressed today. So, I appreciate you being here. If you like this content, be sure to hit like and subscribe. Be sure to follow us because we have more incredible content just like this coming out your way very soon. and I'll talk to you next time.
What About Egg Whites, Methionine, and Homocysteine?
Another argument often made against eggs focuses on methionine - an essential amino acid found in egg whites. The claim is that methionine raises homocysteine, a compound associated with increased cardiovascular risk.
There’s a critical piece missing from this argument.
Homocysteine metabolism depends heavily on B vitamins - particularly folate, vitamin B12, vitamin B6, and riboflavin. When these nutrients are sufficient, homocysteine is efficiently recycled and kept in a healthy range.
In other words, homocysteine elevation isn’t caused by eggs - it’s caused by nutrient deficiencies.
Blaming eggs for homocysteine without accounting for overall nutrient intake is a classic example of reductionist nutrition - isolating one variable while ignoring the larger biochemical context.
Saturated Fat: Still Not the Villain
Eggs are roughly 67% fat, and about 20% of that fat is saturated. This alone has been enough to land them on many “avoid” lists.
But the claim that saturated fat clogs arteries has been thoroughly dismantled.
So why does saturated fat still get blamed?
Because observational studies often show associations between saturated fat and heart disease - but those associations almost always exist in the context of refined carbohydrates, added sugars, seed oils, and ultra-processed foods.
Think about how eggs are commonly eaten today: with bagels, refined toast, sugary cereals, ultra-processed meats, and industrial seed oils. When you isolate eggs and place them into a whole-food dietary pattern, the data flips.
Eggs aren’t the problem. The dietary context matters.
Choline, TMAO, and One of the Biggest Nutrient Gaps in America
Choline is one of the most important - and most under-consumed - nutrients in the modern diet. It’s essential for brain development, liver function, neurotransmitter synthesis, hormone regulation, and cell membrane integrity, especially for pregnant mothers growing a child.
Egg yolks are one of the richest sources of choline in the human food supply, providing roughly 150 mg per yolk.
And that’s exactly why eggs are often criticized.
But here’s what often gets ignored:
There is no high-quality randomized controlled trial in humans showing that TMAO causes heart disease.
Most of the alarming data comes from mouse models or observational associations - neither of which can establish causation.
Even more telling: fish contains some of the highest levels of pre-formed TMAO, yet fish consumption is consistently associated with better cardiovascular outcomes.
If TMAO were inherently dangerous, the Mediterranean diet wouldn’t be one of the most heart-protective dietary patterns ever studied.
The more plausible explanation is that TMAO may be a marker of underlying metabolic dysfunction - not a driver of disease.
Avoiding eggs because of TMAO risks pushing people further into choline deficiency - which brings its own serious consequences based on real, concrete scientific data.
Eggs, Fertility, Pregnancy, and Brain Health
Importantly, choline matters for fathers too. Sperm quality, epigenetic signaling, and early embryonic development all depend on adequate nutrient status on both sides.
Egg yolks also provide fat-soluble vitamins in their most bioavailable forms - including retinol (vitamin A), vitamin D3, vitamin K2, and vitamin E - nutrients that are difficult to obtain from plant foods alone.
Why Eggs Deserve a Comeback
Beyond cholesterol debates and biochemical scare tactics, eggs offer something rare in modern nutrition: a dense package of highly bioavailable nutrients in a food humans have consumed for thousands of years.
They provide complete protein, essential fatty acids, antioxidants like lutein and zeaxanthin for eye health, and critical micronutrients that support hormones, metabolism, and cellular function.
When sourced well - ideally from pasture-raised or local farms - eggs become even more nutrient-rich.
Egg yolks, much like organ meats, function as a natural multivitamin. Removing them from the diet isn’t a health upgrade - it’s a nutritional downgrade.
Final Takeaway
Eggs aren’t the enemy. They never were.
Much of the fear surrounding eggs comes from outdated hypotheses, misunderstood observational data, and a failure to account for dietary context. When eaten as part of a whole-food, nutrient-dense diet, eggs consistently support metabolic health, fertility, brain function, and long-term well-being.
Rather than fearing foods humans have thrived on for millennia, it may be time to re-evaluate the ultra-processed modern diet that replaced them.
Egg yolks included.
