I'm currently a med student after graduating from USMMA
I agree with what was said above, being from any of the academies gives you a slight advantage. Part of the app process to medical school is an on-site interview session and being from the academy gives them something to talk to you about rather than the usual 'why you want to be a doctor' stuff. As said above the rigorous course load at the academies prepares you well for medical school and the MCAT. The MCAT is tough no matter how smart you are, unlike the SAT which tests your knowledge the MCAT is set up to test how well you can learn in the future (not sure how that works, but it's what they say).
An another note make sure to do well at USAFA as only a certain percentage are allowed to apply to med school directly from the academy. As long as you keep your grades up it shouldn't be a problem. And don't major in biology/chemistry unless you really like those subjects. Having a weird major is actually an advantage (anyone else ever applied with a degree in Marine Transportation? it makes you different), major in something you will enjoy.
Best of luck,
![Blowup :blowup: :blowup:](/styles/default/xenforo/smilies2/blowup.gif)
<---is what medical school makes you feel like