How to make a sim lose weight without gaining musculature?

@Serendipity38 This might be way more complicated than what you're looking for, but it's from Carl's Guide, and that's always been a good resource for nitty-gritty no-way-I'd-figure-it-out-on-my-own stuff.

https://www.carls-sims-4-guide.com/tutorials/calories.php