Thursday, February 1, 2018

Musings on Saturated Fat and the Great Egg Yolk Debate

I just got off the phone with my aunt. We were comparing notes on our breakfasts. She had egg whites with spinach pancakes and I had some oatmeal with raisins, almond butter, and collagen powder stirred in. I asked her why she didn't eat the yolks and she raised concerns about their fat content. It's a fair concern, but it got us talking and after we got off the phone, I found a few articles that summarized this topic well.

Here's a great article from Harvard on good and bad fats:

And here's a good summary from Web MD:

Regarding the great egg yolk debate...
For weight loss, I can see the benefit in avoiding egg yolks because any kind fat is high in calories and egg yolks come in at 55 calories per. BUT, by not eating the yolks, you're also missing out on great nutrients (they have a lot of calcium, zinc, magnesium, and a host of other micronutrients that are hard to find in the egg white and in other foods). So, you're getting a few grams of fat but a lot of vitamins and minerals with it that you're otherwise discarding (it took a lot of energy to get those micronutrients into that egg yolk, so that raises a host of issues about sustainability). AND, fats do satiate and keep you fuller longer. They also help control blood sugar spikes and valleys. Eating the white only gives you some protein and a few micronutrients, but not as much as eating the whole egg.

I love this breakdown of the nutrition in an egg white vs an egg yolk. Look at the table to see what you miss if you discarding the yolk!

One of my favorite ways to assess healthfulness of foods is ANDI, an index that basically creates a ratio of nutrients per calorie for whole foods.
You might be surprised to see there that an egg actually ranks higher than olive oil (likely b/c it has protein and a lot more micronutrients).

My view is that it's more important to avoid refined carbs than it is to avoid naturally occurring fat. Trans fat is not naturally occurring and should be avoided at all costs and red meat, which is high in saturated fat, should be limited to once or twice a week or so and consumed < 8 oz/serving. It contains valuable nutrients but can strain your digestive system if you eat a lot of it without lots of fiber!

Remember that many doctors don't have much training in nutrition and if they went to med school over a decade ago, they might have been brought up in the "fat is bad" camp. If they don't continue to read the latest research, they might not have all of the information. The field of nutrition is challenging because there are NEVER conclusive results because humans aren't lab animals and there are too many variables to control for!

How do you feel about fat and egg yolks?