I suspect that you don’t lose weight during sport because of the exercise, but because you can’t eat anything during this time.

Commentary:
β€œAh, the age-old weight loss mystery revealed: it’s not the exercise, it’s the inability to snack that does the trick! πŸ€”πŸ”πŸ’ͺ Who knew the real workout was resisting temptation. πŸ˜† #FitnessHumor”

I suspect that you don't lose weight during sport because of the exercise, but because you can't eat anything during this time.