It messes with the gut biome which in turn limits the ability of the body to process any of the good foods you put in it. Beyond that though studies have shown that artificial sweeteners cause a chemical reaction in the brain where it confuses the brains ability to process natural sugar (fruits veggies etc…) so you use artificial sweeteners and you get the benefits of sweet with no sugar, but your brain tries to process it as a sugar but can’t since it isn’t one. Then, when you eat real foods with real sugar, your body bypasses the proper channels for absorption of those nutrients and you wind up with this mismanaged pile of shit in your body. Scientifically speaking