It takes a lot of effort, but you don't have to feel hungry, and the results will beat exercise by orders of magnitude in terms of pure weight loss!
Though, in fairness to me, his scales would have also shown 0kg if he stepped "on" them!
trying to reconcile this with the conventional advice that weight loss is 90% about eating right
If you have a relatively constant outflow of breath, measurably but not drastically affected by exercise, the CICO conception could still account for the net difference in body mass.
edit: https://www.healthline.com/nutrition/breathing-exercises-for...
the breath thing is how the metabolic waste products leave the body (when your fat gets broken down eventually the mass of it leaves your body as co2).
also, the amount of hours you spend not working out dramatically trumps the amount of hours you spend not working out so working out itself doesnt change your mean..