This is a great question! This was something I was stuck on for a long time.
I used to think this would be an extremely time-consuming thing that would be very annoying to learn. What really struck me is how easy this actually turned out to be. In fact tracking what you eat will save you time. Here's how.
People talk about "counting calories". But here's the problem with that: you can eat nothing but donuts throughout the day and stay within your calorie limit, yet it's still unhealthy. What gives? How do we know what is healthy and what isn't?
Enter macros. Calories in food are made up of three "macros", which are: fat; carbs; protein.
So just forget about calories. What you want to know is how many macros you need per day; how many grams of fat, grams of protein, and grams of carbs. The calories will work themselves out.
Okay, how do you find out? Super easy. You can use a calculator like this one: https://www.bodybuilding.com/fun/macronutrients_calculator.h...
For me, every day I aim for:
154g Carbs
150g Protein
32g Fat
Now you might be thinking "Wow that sounds like a pain in the ass to track. How is it even possible to track that?"
There are apps that do this for you. My favorite app is called "Macros" https://play.google.com/store/apps/details?id=com.josmantek.... and there are a lot of other good ones out there.
Here's how it works:
1. Look at your food nutrition label (for example, fat-free Greek Yogurt)
2. Find the serving size (170g) and enter that into your app.
3. Find the macros grams (0g Fat; 7g Carbs; 17g Protein) and enter those into your app.
That's it. Your app will now have the nutrition facts of that food item saved forever and you only need to follow this process for new foods / new ingredients. Over time, you will gradually build a library of foods you like to eat.
Whenever you're ready to eat, you select one of your saved food items like "Greek Yogurt", and it will simply ask you the weight of your food. Enter in any weight you want, and it will automatically calculate how many macros/calories it will provide you. If it's too much, adjust the weight down, and if it's too little then adjust the weight up.
Once you decide on the perfect weight / macros, then you use your food scale to get exactly what you need.
To wrap things up, this also saves you time because now it enables you to plan ahead exactly what you want to eat and how much you want to eat. When it's time to eat, you just open up your plan and follow the instructions, no more staring blankly into the fridge.