why do some people have to drink magnesium citrate and then also use 2 enemas before...

I never had to do anything before my surgery - just nothing to eat or drink the night before.  I was even allowed to take my synthroid, allergy and blood pressure meds with a tiny sip of water in the morning.

I didn't even had to go on a special diet for the few weeks prior - just told me to do whatever I felt comfortable with since I was a lightweight and as long as I lost something = I lost 12 pounds in 2 weeks, we were both very happy with that.

Every doctor is different.  There is no "one way" for this surgery.  Some patients are allowed solid food before others, some have no pre-op, some have weeks of only liquids, etc.

 Doctors suggestions vary widely.

 Because doctors are completely nuts and can't agree on ANYTHING! 

True, that!

(married to a doctor....worked with MANY as a nurse....)

I don't remember doing a bowel prep; and I'm CERTAIN there was no pre-op diet.

Because in some areas of medicine, there are no studies to help develop established protocols so each doctor does what makes sense to them.

This is one of those areas.

You can see a general consensus that you should be NPO after midnight but then some doctors kind of pile on to that in an effort to clear out the tummy and bowels. How much prep they require depends on their prior experiences, how risk adverse they are, how they feel about their patients, etc.

"how they feel about their patients, etc."

Mac, are you saying that my surgeon didn't care about me since I didn't have to do bowel cleansing and enemas? LOL!

Actually the opposite!

Seriously, haven't you noticed that some programs treat their patients like they are little kids who can't be trusted? They micromanage all their choices, make them do twice that most programs require (on liquids twice as long, take twice as long to introduce certain foods, have twice as many non-medical pre-op requirements, etc., etc.) and set up their programs to be completely "foolproof" because once someone didn't follow the rules so now all the patients are treated like idiots who won't follow the rules.

Then there are the programs that are full of "fatty hate" treating their patients like they are lazy and/or disobedient people who have to jump through hoops to prove they are worthy of surgery. And good forbid you have any troubles ... it's all your fault if you do. You couldn't be throwing up due to a stricture, it has to be you are eating too fast, and god forbid if you regain -- you clearly "didn't learn anything" having this surgery and they will not test you for medical issues like a thyroid problem or edema.

I started out in a program like that. Everyone had to lose 10% of their excess weight even though there is no scientific support for that practice and they'd even cancel surgery if you showed up .5 lb short of the weight loss goal they set for you. It was ridiculous.

Uggghhh!  Mine fell somewhere in the middle.  They wanted 2 weeks of shakes and fresh, raw veggies pre-op, but that was more to get you accustomed to eating less (particularly in the way of refined carbs) than for any other reason, and to detox from sugars and junk.  If you qualified for surgery on your first visit, then all they asked was that you not go on a food binge pre-op and gain oodles of pounds.

Their introduction of foods post-op is a bit slow, but they will tweak it if an individual is healing well and able to tolerate it.  My only gripe is that the best nut in the practice left for a hospital closer to her family that paid better (which I certainly understand!), and the current nuts (noots) are nuts (nuhts) as they continually recommend lots of whole grains and getting off protein early (all, not just shakes), and taking 2 Flintstones daily, not even 4 of the danged things!  Oh - and they're FINE with collagen whey.  Idiots.

I won't see any of 'em anymore, and the surgeon has no problem with that as long as my labs and health remain good.  They're hired by the hospitals, not his practice, so he has little to no control over them.

Not eating after midnight has more to do with the anesthesia than the actual surgery.

I was on a low cal diet before the surgery and had to do mag citrate, but no enema.

My mom was on liquids 2 weeks before surgery but no bowel prep.

Every surgeon is different.