People keep repeating it because once you figure out your motivation and dial in a calorie goal that lets you lose weight without feeling like crap, it actually works. You're right that you can't ignore all that other stuff, but you also can't lose sight of the essential fact that you lose weight by eating fewer calories than you burn. The process of dieting requires you to perform tasks that support that goal.

It's a fundamental part of our physiology that we have to consume a certain quantity of macronutrients to support our metabolic processes. If we don't, then our bodies utilize existing stores of macronutrients like fat and muscles, breaking them down and converting them to usable energy to meet the deficit. This causes you to lose weight, as you drink water, metabolize your fat and muscle tissue, and then exhale carbon dioxide, and excrete waste products. You're literally breathing the weight out.

You find motivation so that there's something preventing you from stuffing your face with cake every day. Then you spend a few months iterating while you figure out what you can build a diet out of that will leave you sated and allow you to cut calories. This is where your metabolism, psychology, etc. come in. Once you have that dialed in, and you may arrive at it without counting calories if you're careful, then you will start losing weight.

Weight loss requires a lot of self-awareness and attention to what you enjoy or don't enjoy about a variety of foods. Somehow, through some series of test meals, you figure out that you really like raw bell peppers, but only with salt, or that the only thing trail mix is actually good for is making you hungrier(this is something I struggle with).

> dial in a calorie goal that lets you lose weight without feeling like crap, it actually works.

This greatly describes why so many people have a problem with the blanket statement "Eat less calories than you burn and lose weight.", because it implicitly contains the crux of the matter.

There is no such thing as a single, straightforward "calorie goal that lets you lose weight without feeling like crap". It varies wildly depending on the composition of your diet (which is even different from person to person) and accompanying factors like amount of physical excercise, sleep patterns etc.

And those are the deciding factors. The calorie deficit is a prerequisite, but the difficult part is in finding a way to sustain it. (I mean, you go there yourself in the following paragraphs.)

But the statement alone is borderline useless and actually quite condescending to anyone with a modicum of diet expierience. It's like saying "Answer enough questions correctly and you'll pass the test." Duh, No shit, sherlock.

I think the point is that in order to take in less calories than you burn, and stay vaguely healthy, you need to be aware of what you're eating, how your body processes it, and how to avoid the temptation to eat more. If you're not eating the right sorts of foods, then you're going to wind up hungry well before your next meal - which isn't conducive to an ongoing diet change.

Part of "that other stuff" is that the body do not burn or metabolize consistently when you change diet. For example, the body can go into a starving cycle which increase metabolism, lower energy usage, and make you less sated, and which reportedly takes a rather long time to recover from. It should not be that surprising that the human body has evolved to adapt when food availability change.

Perhaps, but if everyone around you was using molasses instead of rocket fuel and pointing their spaceships at the side of the mountain and then posting "I've tried everything I don't know why I'm not soaring in space yet" on Facebook you might start by reference to those basic principles.