I'm going to take issue with the majority of folks here and insist that dieting does not cause "low blood sugar". That is one of the most ridiculous things I've ever heard. I've been on a diabetic diet for over two years and have never measured my blood glucose at less than 70 mg/dl (3.9 mmol/l). It's usually between 80 and 110. Low blood sugar is considered by most as being lower than 60 to 70 mg/dl. I've even fasted and not seen anything lower than 70.

FYI, even if you don't eat anything at all, your pancreas produces a hormone called glucagon which causes the liver to convert stored glycogen into glucose in order to insure that you have adequate levels of glucose in your system.

http://en.wikipedia.org/wiki/Glucagon

Now, taking too much insulin or other blood glucose lowering agent might cause low blood sugar, but think about it... how can being on a diet lower your blood sugar? I know of no diet that is completely carbohydrate and sugar free and certainly has no blood glucose lowering agent in it. Come on, people.

And I doubt very seriously that anyone here exercises enough to lower their blood glucose more than 20 points. (I know how much it takes... I've done it).

Let's reiterate... you asked: "can being on a diet cause low blood sugar?" When one reads the words and understands what they mean, there is no possible way one can truthfully say "Yes". No diet I know of or ever heard of can (directly) cause low blood sugar. Not even that ridiculous Atkins diet. The only reasons I can think of for so many erroneous answers is:

A.) most people didn't read and understand the question or, B.) most people are sadly misinformed.