How is it even possible to be in a 300 cal deficit?

So I see a lot of stuff online and on the sub saying that being a 300 cal deficit is ideal for cutting while maintaining muscle mass.

The thing is I feel like it’s impossible to be that accurate with your calories.

First of all we don’t have the technology to accurately tell you exactly how many calories you’re burning every day. Fitness trackers have like a 500 cal margin of error. Those online calculators are literally pseudoscience. Literally the best method we have for figuring out maintenance is to guess-and-check, and even then your body is gonna burn different amounts on different days.

On top of this, it’s almost impossible to gauge that small of a margin of error within your food too. Nutrition labels can be 20 to 30 cal off, obviously portion sizes can vastly affect how many calories you’re eating, etc.

According to Google, one scoop of peanut butter is 188 cal. That means that two scoops of peanut butter is enough to make or break your entire diet.

I feel like a 300 cal deficit is just way too small to be realistic for 99% of the population.