The sugar reserves in your liver are like a last resort of your body when it can't burn any carbohydrates in the cells. As a type 1 diabetic I can tell you that you shouldn't fuck with that at all. Messing up your hormones (like insulin) is a really bad idea. Apart from that we obviously consume too much sugar. When your liver dumps all the sugar it saved up it also dumps a heap of the shit it is supposed to filter out. When you get hypoglycemic and your liver takes over, you gonna have a really bad time. When your body burns fat it produces Ketone, which is similar to acetone (or nail polish). In small concentration that's not a concern, but in higher concentration, like when you don't consume any carbohydrates, it fucks you up big time. Ketone is the reason why diabetics get blind, lose their legs and develop nerve damage.

Sugar is only toxic when you get it from refined sources. When you consume whole, intact foods, in a balanced diet, sugar is totally fine and literally our primary fuel source. Our metabolic system prefers sugar as fuel so greatly that it 1) will use it over fat if available, and 2) will break down proteins in the body to get more glucose if deprived of it.

How's that acetone breath by the way?