So, for instance, when I want to maintain weight, I eat moderate carbs after I workout. If I want to gain weight, I'll eat more carbs, and higher GI carbs, after I workout. If I want to lose fat, I'll do the 6.5 day refeed approach (this was nutshelling in its heaviest form....there are many nuances, but you should get the idea).
You don't have to gain the weight back. Just realize what made you successful and start adapting that to how you live after you hit your goal, whatever that is.
These days I have lost enough fat that I can, by eyeballing, see what I had for dinner the night before. Lots of carbs --> retain water --> some veins disappear. Few carbs --> less water retained --> veins more visible.
At the moment I try to schedule particularly carby dinners for hypertrophy days, on the theory that this will work better for sarcoplasmic hypertrophy purposes.
But at this point in the discussion I am well and truly majoring in the minors. The headline is still that I am losing fat through caloric deficit and that for me, the easiest way to do so is intermittent fasting.
They used a factory-calibrated scales, which uses impedance to measure your body fat percentage.
I don't trust the measurements: if you're using impedance to measure it then hydration and the salt balance in your body will dominate any small scale changes in body mass (7kg is < 9% of my body mass).
The initial measurements look anomalous, the muscle % and fat % were well out of bounds with my girth/height when compared to the US military-sourced base lines.
It works really well for fast weight loss: in 12 weeks, 22kg fat burnt and 7kg raw muscle mass added (if the measurement is to be believed).
Sure, I've gained 15kg fat back since I stopped, but that's the Achilles heel of all diets..