Smoking and Gastric Bypass Surgery

Unfortunately some patients are not truthful to their surgeon.
This will only effect them in a negative way. Smoking not only will cause LUNG CANCER and HEART DISEASE, it will also increases the chance of major complications after any elective surgery. 
Cosmetic surgeons and Weight Loss surgeons, in particular, will not advise surgery on anyone that smokes. The more you smoke, the higher risk of complication like staple line leak, and ulceration.
Most physicians don't check with any blood, or urine test for nicotine level, and trust their patients. This trust should be on both sides between the patient and surgeon.

I sort of agree with your surgeon.  I also don't operate on anybody who is an active smoker, but I STRONGLY urge patients not to start smoking again once they have had their surgery.  Unfortunately I have a lot less control of a patient's smoking behavior after surgery.  Here are some of the reasons why I don't operate on smokers:

1)  Smoking increases the likelihood of the two biggest killers of weight loss surgery patients in the early post-operative period:  leaks and blood clots.  By getting someone to stop smoking at least 6-8 weeks before surgery it likely makes it safer for them to undergo the surgery on many different levels.

2)  If someone can't stop smoking before surgery, why would I think that they would be committed to make the OTHER very difficult and challenging lifestyle changes (dietary, behavioral, and exercise) that are needed after surgery to create long-term success?

3)  Patients that start smoking after their gastric bypass often will get ulcers at the connection of their pouch and small intestine (gastrojejunal ulcer).  These ulcers can be VERY difficult to treat and I personally have had to do two gastric bypass reversals because the patients developed ulcers that would not go away and they refused to stop smoking. 

4)  I went into medicine to make people healthier.  If I can use my "power" before surgery to help (some would say force :) ) someone to stop smoking, which we KNOW will improve their health, I would be remiss if I didn't use that opportunity.  In my experience, although some patients will start smoking again after surgery, many will not.

Stopping smoking is hard.  Really hard.  But smoking and weight loss surgery really don't mix well and the results of smoking, unfortunately can be disasterous.