One more thing, breaststroke also depends on the intensity. If the competition intensity of professional players is three hours, you can consume a lot of fat in a month, but if you swim slowly for three hours, you can see the effect in a month. Seriously, it must not be as big as you think. And the amount of weight loss depends on your own situation. No one will know how many pounds you will lose in a month through a certain exercise, unless you exercise with high-intensity slimming equipment without considering physical injury. In that case, if you have perseverance, you may be able to develop your abdominal muscles in a month.
Of course, swimming is not necessarily slow. There is a real case in our swimming pool, madam. I swam at high intensity for a month every day and lost 40 pounds.