[inglor_cz]

N == 1, but when I eat in certain way (lots of veg + fruit, reduce white bread and pastry, no caloric drinks), my body stays the same weight, as measured by clothing size, without any further conscious effort.

I suspect that this is the way how our ancestors in the 1950s-1970s stayed slim (at least compared to us) without calorie counting or even knowing what calories were, even though they held white collar jobs too. Body tries to find an in/out equilibrium, and ultra processed foods disrupt this process.

Take any photo of an engineering or academic team from that period and compare it to a photo of people doing similar jobs today. A massive difference in size, though the job's physical demands aren't that different.