It is a lot more complicated than people seem to think, too complicated to cover all the basis in a simple infographic but I tried my best.
Conventional thinking seems to be that if your weight is neither increasing nor decreasing, then whatever you happen to be doing now is "your maintenance" level of calorie intake. Whether that is working to / restricting to a particular calorie limit, or otherwise. If you're not losing & not gaining weight you're "at maintenance".
This can be problematic in cases where you have active people who are working to calorie limits and not seeing progress. Whether that is "weight loss progress" per se or whether they are already at around an appropriate goal weight but perhaps not at goal condition. The conventional (lack of) wisdom dictates that if you're not seeing fat loss progress, you're "at maintenance" and need to cut lower to get back into deficit.
Not necessarily so, and in my opinion, observations & experience not even the most likely explanation.
In actual fact, "maintenance" is not some pin point specific amount above which you'd gain weight and below which you'd lose fat. In actual fact there may be quite a wide margin between where (at the higher end of the spectrum) your intake is not high enough to gain weight, but is too high to draw from fat stores, and (at the lower end of the spectrum) your intake is insufficient to facilitate improvements in condition via prioritisation of lean mass, and your productivity & performance at training as well as your Non Exercise Activity Thermogenesis is sacrificed in preference to drawing from fat stores.
Somewhere in between is an optimal range of calories where you can expect improvements in performance, energy & resources to be used to support increases in lean mass (at best) at the expense of fat stores or at least while not adding to them.
TL;DR it's like I've been saying for YEARS now and a few other people are starting to catch up to; you require an adequate but not excessive amount relative to your requirements as primarily determined by your amount of & level of proficiency at training, amongst other things. When you cease to see progress you must assess the situation accordingly rather than just assume that you need to eat less. And you do have options other than "bulk w/ fat gain via calorie surplus" & "cut w/ lean mass loss via increased calorie deficit".
