At work, my assistant recently had problems with gall stones, and it reminded me of my experience with them. A few years ago, after losing a lot of weight following Weight Watchers (low fat, high carb), I had a medical exam by a urologist and he told me I had a nice set of gall stones. He further went on to say that most people who lose weight get gall stones, but that if the stones stayed in the gall bladder, I wouldn't have to worry about them. Based on what he said, I didn't think any more about it until recently.
Fast forward to my low carb lifestyle. After learning about my assistant's problems with gall stones, I started doing some research and found this article on low carb diets and gall stones by the remarkable Michael R. Eades, M.D. The basic issue: low fat diets can cause gall stones. Low carb diets prevent them. Why?
According to Dr. Eades, if one eats a lot of fatty meals (e.g., a typical low carb meal), the bile secreted in the gall bladder routinely empties itself and stays free of gall stones. If one does not eat a lot of fatty meals (e.g., the typical low fat, high carb meal), the cholesterol component of the bile supersaturates and condenses to form gall stones. If they stay in the gall bladder, no problem, but if they are excreted, they may cause various forms of blockage. I guess that means that following a low fat, high carb diet like Weight Watchers could have caused my gall stones to develop, whereas they probably wouldn't develop by following the low carb lifestyle.
Read the article linked above for all the gory details, as Dr. Eades does a much better job than I do of explaining it. But it boils down to this: The traditional "Healthy" low fat, high carb diet may also cause you to develop gall stones. A low carb diet helps prevent gall stones, in addition all sorts of benefits (e.g., weight loss, improved blood glucose control, improved lipid profiles, lower blood pressure), especially for type II diabetics.