I'm really glad to see this discussion. I've seen posts from some pre-ops (not here - elsewhere!) being afraid of the DS because they don't want to eat tons of fat, and I've tried to explain that a high fat diet is NOT a requirement of the DS, it's just that we can eat fat in reasonable amounts (like butter on veggies, oil in cooking, etc etc) and this is ok.
Also, I agree with [USER=878]@DSRIGGS[/USER] regarding lab values. There are some studies out there showing that there really is such a thing as too high a Vitamin D level, for example, and excess zinc can cause copper level to drop, which in turns causes non-iron deficiency anemia. I'm sure there are lots more possible examples. While we tend to worry more about levels being too low due to malabsorption, we can be harmed by too high levels, just like anyone else.