Is it a good idea to study under a BS/MS or BS/PhD program before applying to medical school? Or is this looked down upon by the medical school admissions committee?
A PhD will likely be seen as a positive by most admissions offices, but it would obviously take many years of work to successfully complete one, so I wouldn't advise it for admissions alone. I'm not sure how much a master's would really be considered by med schools, so again, I'd only do it if you have a particular interest in it.
people only care about your degrees to the extent that they factor into your journey to medicine and whether or not you meet requirements and expectations for admission.
alternatively, getting a PhD before an MD is pretty pointless if you know you want the MD beforehand as an MD/PhD program will pay for your medical school unless you’re doing some kind of prestigious scholarship like Rhodes/Gates for the PhD