That's exactly how I came to lose all the weight I have - I started counting calories which caused me to treat it like a budget. I never deprived myself of what I wanted, but new if I splurged on supper I'd not be able to do as much dessert.
Unfortunately, the body itself is a complex system, and likes to throw curve-balls. Going by some of the things I've read over the years, it's clear the body has defense mechanisms against starvation - such as lowering metabolism and activity levels in lock step with diminished caloric input, or turning you into food-obsessed zombie, hardly capable of a non-food-related thought, until you feed the body enough to cancel red alert. Problem is, for some people, those defense mechanisms seem to kick in before they reach negative energy balance. As simple as calorie counting is, it's not helpful if the body hits the "override" switch before you reach Calories In < Calories Out.
I don't know if there's a solution for this case, but I suspect all the variety of diets is really just people doing a blind search in hopes of finding specific tricks that shut down the defense mechanism in subgroups of individuals.
(In a sense it's like a puzzle game: your goal is to sneak past a security system without raising an alarm. The security system consists of a great variety of sensors of all kinds - but only a random subset of them are in use, configured with random thresholds. Every player gets their own, unique puzzle.)
>lowering metabolism
I believe this has been debunked. Your calories out is a function of calories in (e.g., protein takes more energy to metabolize than, say, glucose), but your body doesn't really downregulate it's metabolism the way it's been touted in the past.
>search in hopes of finding specific tricks that shut down IMO, what consistently works is whatever "tricks" you use to reduce calories below what you burn. For some people, it's eliminating meat. For others, it's eating nothing but meat. For others, it's a flexible approach as long as they count calories. But the main commonality seems to be the reduction of calories (and movement away from the standard american diet).
The nutrition info is "in your face" for a reason. Use it.
How many calories on that bag of chips? On that big cookie you ate? On that fast food sandwich/burger?
On that soda which is 100% empty calories with a high GI?
The biggest fraud in nutrition has been replacing high-caloric food that actually help with satiety (high protein/"high" fat/high fiber content) with sugary crap
Simply ≠ easy.
What to slow/stop/reverse climate change? Simple: "just" reduce carbon output.