A friend emailed me to ask a question about nutrition. "What are macros? Are macros a thing? Are they important?"
Quick answer: yes, macros are a thing, and yes, they are important.
Crash course: There are two types of nutrients. MICROnutrients comprise the stuff we need tiny amounts of -- riboflavin, vitamin K, etc. MACROnutrients (a.k.a. macros) are what we need large amounts of every day: protein, carbohydrates, and fat.
Macros are important because they each behave differently in the body, and in improper ratios can screw up your progress in the gym.
The old "calories in, calories out" idea of weight loss is extremely outdated. Your metabolism is not a checkbook you can just balance through simple addition and subtraction.
For example, people who eat a high-protein diet typically have an easier time maintaining a healthy weight, partly because protein costs the body energy to break down, meaning the usable calories you get out of a serving of protein is less than the same number of calories from carbohydrates and fat. For the same reason, a person aiming to gain weight would want to eat sufficient protein to build muscle, but would be smart to make up the extra calories in carbs and fat.
And, as always, it's possible to have too much of a good thing. People who chronically overeat protein and under-eat carbs and fat will eventually find their energy levels sinking, and their fitness stalled.
So what is optimal? And how do you keep track?
Opinions vary, but 45/35/20 is a great place to start. I.e., 45% of your calories should come from carbohydrates, 35% from protein, and 20% from fat. Some people may thrive on a different ratio, and that's just fine. The beauty of tracking macros is you can find what works best for you.
As for tracking, these days it's incredibly easy. The past few days I've been tracking my own macros with an iPhone app called "MyFitnessPal." It's free, and I love it. You simply enter what you eat, and it will calculate your macro breakdown and total calories. The coolest feature is that it uses your phone's camera as a barcode scanner. You don't have to type in the information; you just scan the food and type in how many servings you eat. It takes mere seconds.
Here's a snapshot of my last few days of eating. As you can see, my fats are pretty high. That was surprising to me (although cheese IS my favorite food), but after seeing that pattern emerge, and given my goals of building strength and keeping my energy up, I'm trying to emphasize more protein and carbs in my diet.
This is the true value of tracking macros: not agonizing over every little gram of food, but rather seeing patterns and recognizing your own habits so you can slowly start making better choices.