How Healthy Are Eggs, Really?

Eggs are kind of like wine: People have a preference for how they like 'em (sunny side up versus hard-boiled, red wine versus white). And everyone seems to have an opinion on whether or not they do you any health favours. The latter question has been debated by researchers for years—and studies support both sides. Let's unscramble the latest.

Eggs have essentially become synonymous with protein. And with 6 grams of the muscle-building macronutrient and just 70 calories each for the average large one, eggs deliver one of the healthiest ratios of (animal-source) protein to calories, says Ryan Maciel, RD, the head performance-nutrition coach for Precision Nutrition.

About 60 percent of that protein is in the egg white, and the remaining 40 percent is in the yolk, according to the USDA. "The whites also contain leucine, which is a branched-chain amino acid that has been shown to increase muscle repair and growth", says Maciel.

The yolk, on the other hand, also packs fat and cholesterol, which has led many people to criticise and avoid it, says Maciel. But the yolk actually contains most of the vitamins and minerals, including the essential nutrient choline, he says, which is important for heart and brain health, and which most of us don't get enough of. Yolks are also one of the few dietary sources of vitamin D, according to the National Institutes of Health.

Plus, eating the whole egg could help fast-track your efforts in the gym. A study published in "The American Journal of Clinical Nutrition" found that when people ate about three whole eggs right after a strength-training workout, their muscle-building response was 40 percent greater than it was for those who ate a protein-equivalent meal of just egg whites. Other compounds in the yolk may help your body use the amino acids, including leucine, that eggs contain, say the study authors.

Going back to the cholesterol concern for a minute: A large egg packs about 180 milligrams of the waxy substance, which, if it builds up, can clog your arteries and lead to cardiovascular issues, according to a study from the National Heart, Lung, and Blood Institute. But researchers have also found that most of the cholesterol in our bloodstream is made by our own bodies—and when we eat cholesterol, our bodies might actually make less to balance it out. In fact, a 2018 study that followed more than 400,000 people found that those who ate an average of one egg a day had a lower risk of dying from a stroke or heart attack, perhaps because of the heart-healthy nutrients eggs contain, such as antioxidants. (Don't get too excited; this doesn't mean eggs are medicine).

That said, there's a limit to their heart-healthy benefits. In 2019, a large study from Northwestern University found that the more cholesterol people consumed or eggs people ate, the higher their risk of cardiovascular disease. Eating 300 milligrams of dietary cholesterol (less than the amount in two eggs) per day was associated with a 17-percent higher risk of cardiovascular disease. While some people metabolise cholesterol quickly, meaning it doesn't impact their blood levels, that's not true for others, say the researchers.

And if you've heard rumours that eggs might cause cancer, you can ignore those for the time being. The real downside to eggs is their potential cardiovascular consequences, says Meir Stampfer, MD, a professor of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health. "Some people have proposed that eggs are a risk factor for cancer, but the evidence is not compelling".

In light of all this, experts recommend cooking up no more than half a dozen eggs in a week. Dr Stampfer notes that for most people, though, "one egg a day is fine". (Maciel says two a day is probably OK if you aren't consuming many other sources of cholesterol and don't have a family history of cardiovascular issues). But both experts say that if you have concerns, talk to your doctor, as you may want to limit your intake further.

To figure out the right amount for you—as with any diet choice, this one's personal—consider what you'd replace eggs with, suggests Dr Stampfer, who himself eats a few each week. If cracking fewer shells means you'll start eating more processed meat for protein, for example, stick with the eggs. But if you'll swap in whole or minimally processed foods, like oats, a few times a week instead, then do so. Either way, when you do eat eggs, try not to pair them with foods high in saturated and trans fat (ahem, bacon and sausage), says Maciel, and scramble them with vegetables and stick to a side of wholegrain toast instead.

Oh, and if you're using eggs to supplement your training (smart move), eat them as a pre- or post-workout snack within an hour or so of your workout, says Maciel. When paired with carbs, like fruit, the fat in eggs can help slow digestion, stabilising blood sugar levels so you don't crash during your workout. And after a session, the mix of protein, fat and micronutrients can fast-track your recovery. Just don't pull a Rocky—eating eggs raw is definitely not a good idea.