Losing just a few pounds or even 10 pounds will not affect your surgery one way or the other. An unhealthy crash diet is certainly not recommended. Rather, a good, healthy diet with lots of protein is worthwhile. Sometimes, supplements with extra Vitamin C and Zinc may be helpful.
However, if you plan on losing substantial amounts of weight, then surgery should definitely be deferred until the weight is lost and you are stable at the new weight. Then a re-evaluation may be necessary in order to assess the specific type of surgery required for your new shape.
