Weight loss depends soley on calorie balance? I think not

Weight has, despite watching points, stayed constant-ish for a bit, even drifting slightly upwards.
Yesterday, I ignored the points, ended the day with a slice of full-fat cheesecake, and had an unmeasured but large quantity of alcohol.

I lost a kilo overnight.

I also got 8 hours sleep rather than the usual 4. Correlation? Looks like it. Causation? Could be...

Time for another nap.