It’s basically water, protein, and a couple of nutrients in small amounts.
It’s got triple the calories of the white, almost as much protein, and a wide range of nutrients including:
- Choline: Choline is an essential vitamin-like nutrient that plays a number of important roles within the body, including the production of the crucial neurotransmitter acetylcholine. Choline is also a major player in lipid metabolism and helps to increase neurotransmitter production.7 It just so happens that eggs are one of the best sources of choline.
- Vitamin D: This fat-soluble vitamin offers far too many health-supporting and muscle-building benefits to list here. Unfortunately, it’s hard to find in food sources without enrichment.8 For this reason—and because we don’t get enough time in the sun—deficiencies are rampant, which can have serious health implications, particularly on the immune system. Egg yolks won’t solve the problem on their own, but they’re an important part of a multifaceted approach.
- Additional fat-soluble vitamins: Egg yolks are also a solid source of vitamins A, E, and K, all of which require adequate dietary fat for absorption. You’ve no doubt heard that taking your daily multivitamin with a meal is a great way to optimize absorption. Yolks are like a multivitamin all on their own—or a great way to make sure yours is working.
If building muscle is your goal, including the yolks is a no-brainer. Whole eggs are rich in leucine, have a rock-solid amino-acid profile, and are about as affordable a superfood as you could ever hope to find. As for those extra calories, well, you’ll need them if you want to add muscle.
To be clear, the deciding factor in your weight-loss journey is whether or not you’re eating a variety of nutritious foods while in a caloric deficit.
There is a case for whole eggs, though. Consuming more fat has been shown to help keep dieters feeling full longer than a diet low in fat, while also optimizing their hormonal profile. Going very low-fat, we now know, is a bad idea for multiple reasons, and can leave you feeling awful.