And you can also bounce back to your original weight afterwards, which is something I find fascinating.

There are some working theories (with some amount, but not enough yet of good science) this has to do with your gut microbiome. Since these bacteria are a critical (and still largely unknown) link in not only our digestion, hormone response, nutrient absorption, and immune/inflammatory response.

In essence, a particular set of gut bacteria are good at breaking down certain types of food in certain quantities, and they’ll tell your body to keep giving that type food and quantity. So unless that’s changed with longer term dietary changes, you’ll return to your previous state because thats what your gut is telling you to eat keeping your original cycle.