You can pretty easily tell the difference.  The type of person who gets complacent and fat in some stage of marriage or having kids will have apparent self-control issues and will do the bare minimum to maintain a decent weight and will complain about how hard it is to resist sweets or how much they dislike exercising.  Really, any future ham wears it on their sleeve if you pay attention. A true shitlord or lady is someone who actually enjoys taking care of their body, which is also not hard to spot.  You will always see them think twice before they do something potentially damaging to their body, and they will have some active hobby that they love doing and never plan on giving up.  It could be dancing, exercising, walking, hiking, yoga, etc.