Recently, I have been faced with clients with stomach bypass surgery to lose weight. After surgery, the studies tell us that the metabolic rates change. For example, in a 150 pound female, one drink (4 oz. wine) would normally contibute a .03-.035% BAC and will peak in about 40 minutes. After bypass surgery, that conribution can go up to .08% BAC! So watch what you drink and how much after bypass surgery. Realize also that the BAC rises more quickly, to 15 minutes. Therefore if blood is drawn 1 one hour after the last drink, the BAC will be much higher than at the time of driving. This is relevant to the impairment portion of the charge as symptoms get worse, fast and stay that way longer.